It was actually my Nexus One's internal storage limitations that taught me how to be frugal with storage. It had an sd slot but not all apps could be moved to it and Nexus One had less than 200mb internally. Limitations taught me to be creative and frugal, which led to being efficient with storage space, RAM, battery life, and price value. Thanks, Android. Being kinda sucky back in the Gingerbread era made me wiser. We learn more from mistakes than successes.
I really only use about 40 apps with Android. Same ones I have used for 3+ years. With iOS, maybe less than that since it doesn't have the system or maintenance apps I need. With that said coming from someone like me who is very efficient with storage space and would even list the videos on my phone depending on its size, avoid 16gb like a plague. Imagine recording an HD video but you ran out of space when the special moment happened?
My personal bare minimum is 32gb if I don't store 30 of my favorite movies and most are in 720p. My phones with 64gb have about 9gb left if I store my 30 fav films since it eats over 20gb. But if I don't store much HD movies, 32gb is sufficient enough to store all my photos and music with about 15gb for other stuff. Impossible for me to store all my videos since I can reach 2tb if I really wanted to. But I am picky with the videos stored in my phones.
If you aren't a gamer, videos is the biggest culprit in taking up the most storage. Photos and music are starting to have similar sizes too now that the default megapixel count goes up. Taking over 250 photos can eat up as much as 1gb. You take 1000 photos, that's 4gb! Think ahead since in the next few years, you may take alot of photos. It is possible to live with 16gb if you clear out most of your media, only text and browse on it, and only store very little media and apps, but I wouldn't try it again.
Sucks when you want to show a random video or photo to someone but it is on my "other" phone with an sd slot at home. Internal storage ONLY sucks monkey balls but you got to live by Apple's rule. Always get more than what you need right now because the future software and media can get bigger later. Be forward thinking with your storage space. Never be short-sighted or you will regret it later.