Will 1GB of data a month be enough for an iPhone?

I'm thinking of getting an iPhone, but only the small plan, which has only 1GB of data a month.
The only thing I go on the internet for on my phone is Facebook.
Will it be enough data?
Or will it be constantly looking for updates and stuff and use internet data? My old phone did that and took away heaps.

I use 250mb of data and that's more than enough for just facebook alone.

Possibly. But be careful that you don't have notications on your phone for email and facebook. Because when its idle and sleeping. It will still get info when your not using it.

You know, it honestly isn't. I would get. 2GB
I have an iPhone 5 and 2GB is enough for me. I use Facebook, surf the web, download, and get on YouTube. I'm also Hooked up to Wi-Fi all the time and still use more than one. If you don't use Wi-Fi get 3 or 4 GB even though that's hella expensive.

It depends on the person. I use at least 5Gb a month.

Give your phone at least 4gb of data space. Down the line you might want to change your mind and download more than you think like music, movies etc. It's a better bargain than buying a new phone with more space later on if you change your mind.

Besides, downloading updates, system firmware apps etc.requires enough space just to reboot and 1gb is honestly not enough.