[mynameisvlad]

You are right, your quota will depend on when you got the account and what you did. At various times, we had 5, 7, 15, and 25GB for free. When the big nerf happened from 25 to 7 (I think that's the one you're talking about), existing accounts could opt in to 25GB (personally, was not a fan that it was opt-in) for life. Same thing happened to the O365 offering, nerfed from unlimited to 1TB which is more reasonable, I don't know why anyone would offer unlimited storage honestly, that's just an open call for abuse.

Edit: For me, after Apple actually decided to integrate iCloud into macOS, I felt more secure about it staying, but before that it definitely felt like a pet project that might be abandoned. I still don't fully trust it with my documents, but since I have an iPhone, I have well over 15GB of photos and videos uploaded that I'd like to see stay for a while. :)