If you use the Henle app you'll be aware that one uses credits to purchase scores.
I just got an email saying their credits will be discounted 25% between 11/27 and 12/3. I usually stock up on credits on sale to have them available when the impulse to buy something arises. (Pre-sale, now, 100 credits = $9.99 USD.)
While their own app is fine, I generally export the purchased scores from their app and into forScore just to have all my stuff together. (Although some of the annotations and footnotes are only visible within Henle's own app.)