pianoloverus That makes perfect sense. When you wrote I play how I hear it should be played I thought you meant what you think it should sound like but not taking the composer's markings into account.
I thought the same thing.
@keystring Sorry for the nitpick, but I'm curious why you said, "I play how I hear it should be played." instead of 'I play how I see it should be played.", since, after all, you had to see it first before you could hear it.
(Edit: reformatted post)
keystring The actual point I was trying to make is that the most important thing is to know what a symbol is asking you to do in the music. Remembering what that symbol is called in that instant is not important.
I am fully with you on this one. However, my confusion is not "is this curved line called a tie or a slur?" My confusion is: "Does this curved line mean that I should hold the same note in the intervals or chords, or does this curved line mean that I should play the intervals or chords legato?"
*
... feeling like the pianist on the Titanic ...
Kaydia I thought the same thing.
@keystring Sorry for the nitpick, but I'm curious why you said, "I play how I hear it should be played." instead of 'I play how I see it should be played.", since, after all, you had to see it first before you could hear it.
Another interesting turn, which hinges on the other discussion we just had about how people perceive things differently, a thing pointed to me by a teacher who stays mindful of this when teaching.
My music life evolved in a quirky way since I had no instruction until my late 50's. In some ways and contexts I hear things off the page, like you might when you read words (Do you hear the words you read, in your head? I don't know if people do that, either. 
) So the duration of a note becomes a sound that counts out, and I play that counted out sound. There are other things I don't hear off the page.
For this, I think I see and hear simultaneously. Another more standard thing is where you see the note values, and you might chant and clap out the beats like, "da-a-a-a, da da, diddle-da" without piano, and add piano. Maybe a person who does that later hears their voice going "diddle-da" as they play the piano.
pianoloverus keystring That makes perfect sense. When you wrote I play how I hear it should be played I thought you meant what you think it should sound like but not taking the composer's markings into account.
Thank you - that's cleared up then. Maybe my answer to Kaydia cleared up some of it as well.
Animisha I am fully with you on this one. However, my confusion is not "is this curved line called a tie or a slur?" My confusion is: "Does this curved line mean that I should hold the same note in the intervals or chords, or does this curved line mean that I should play the intervals or chords legato?"
I think a way to word the answer is:
If that curved line goes from a note to the same note, then you play those "two same notes" as one continuous note. If the curved line goes from a note to a different note, then you play them legato.
I think in one of your questions there were two voicings in a same clef - one with stem-up notes (voice 1), the other with stem-down notes. The stem-up are one singer's music: stem-down are the other singer's music. So if "singer 1" has the same note twice, then it's a tie = the same note continues as if one single note.
Does this clarify or confuse?
keystring In some ways and contexts I hear things off the page, like you might when you read words (Do you hear the words you read, in your head? I don't know if people do that, either.
Yes, I do hear the words in my head when I read. But in a conversation referring to something that's written, I'm discussing something I read (saw), not heard. For example, I'd say "Did you read that part about...?" vs "Did you hear that part about...?, even if both things were true.
In any case, I understand what you're saying now, so it's all good. Don't want to derail the thread. 
Kaydia Yes, I do hear the words in my head when I read. But in a conversation referring to something that's written, I'm discussing something I read (saw), not heard.
Still thinking about this. The thing is that for these things, what I see (in notation) is also a thing I hear while seeing it. So I may refer to the wrong sense. Never thought about this before.
test: two of my posts have shown up as written by "deleted". I deleted one of them now because it was too wordy anyhow.
keystring I think a way to word the answer is:
If that curved line goes from a note to the same note, then you play those "two same notes" as one continuous note. If the curved line goes from a note to a different note, then you play them legato.
Not quite correct I think. Imagine the notes C,D,E,D,C played with a curved line over them. This would not be a slur because of the notes played between the two Cs.
pianoloverus Not quite correct I think. Imagine the notes C,D,E,D,C played with a curved line over them. This would not be a slur because of the notes played between the two Cs.
Two CONSECUTIVE NOTES understood. In C, D, E, D, C does not "go from C to C" - it goes from C to D. It eventually goes back to C but we're talking about the next note.
@Animisha I used to think it was obvious what a slur vs a tie looked like until I started overthinking it after reading your post 
I was recently working on a Chopin piece and there's a note that looks like a tie but that doesn't make sense, he's clearly using the notation to indicate a phrase. Sometimes it can be confusing! I do think the general rule of "same note is a tie, else it's a slur" is a pretty good one though.
twocats I was recently working on a Chopin piece and there's a note that looks like a tie but that doesn't make sense, he's clearly using the notation to indicate a phrase. Sometimes it can be confusing! I do think the general rule of "same note is a tie, else it's a slur" is a pretty good one though.
Thinking about this - you can also end up with enharmonics when for example the music is in the middle of a key change. So you might have C# tied to Db (if that happens in music) and it is a single note that continues in piano music.
keystring If that curved line goes from a note to the same note, then you play those "two same notes" as one continuous note. If the curved line goes from a note to a different note, then you play them legato.
My confusion arises when there is a curved line, connecting intervals or chords, and one note in those intervals or chords is repeated, whereas the others are not.
But I understand now, finally! that - those curved lines are more exact than I thought. If the curved lines connect the same notes in those intervals or chords, those notes should be held, if the curved line are between other notes in the interval or chord, it is a slur and the notes should not be held.
*
... feeling like the pianist on the Titanic ...
This is so funny!
But I finally get it. Because the curved lines sometimes were above the chords, and at other times below the chords, I thought where the curved lines are didn't matter, but now I realise, it matters a lot.
I can now easily see, in all examples that I have given, if the curved line is a tie or a slur.
*
... feeling like the pianist on the Titanic ...
The position of the curved lines is just a matter of convenience. A tie can be above or below the chords. Same for slurs. Sometimes it is difficult to identify which is which. Often the curved line above the melody is a slur. But with tied chords, I always try different options including to actually repeat the note or the chord in particular when it is held for a long time (Bach for example).
pianoloverus keystring I think a way to word the answer is:
If that curved line goes from a note to the same note, then you play those "two same notes" as one continuous note. If the curved line goes from a note to a different note, then you play them legato.
Not quite correct I think. Imagine the notes C,D,E,D,C played with a curved line over them. This would not be a slur because of the notes played between the two Cs.
I had this backwards. My last sentence should have said this would be a slur because...
