Totally depends upon individual user habits.
I installed 500 GB HDDs in my PS3s over the 7 years I've been using them and the only times I ran into storage issues was when I used to keep a lot of video files stored locally which ate up space fast.
More recently, due to all the free downloads I've been taking due to PSN+, storage space has become an issue due to having too many full retail games on HDD. It doesn't help that I have over 100 games purchased through PSN and have the majority of them installed as well.
With the higher install sizes for PS4 games, it's not difficult to fill up 500 GB, and even easier if you use the video recorder function while you play. They have that offload option in addition to the upload option so that's less of an issue, but it still doesn't take a lot of retail game installs or downloads to fill the drive.
I'll just say if someone buys a lot of games for the PS4 and likes to keep everything installed, even the games they no longer play, 1-2 TB would probably be a better fit. But the typical PS4 player won't need that much space, particularly if they delete their inactive game installs.







