How quickly does 1GB of internet run out?

So basically my dad has ordered me an iPhone 5 with 1GB internet (data) whatever lol. I wanted him to get me unlimitted but he didn't. *sigh*
I go on twitter and instagram ALOT. But i'll be using wi-fi when i'm at home though. But when i'm out and stuff i'll be probably using internet. I approximately use the internet on my phone when i'm out for like 20-30 minutes and i use it for twitter and instagram. How quickly will this run out for me? Do yo think i should reduce the amount of time that i use interent on my phone when i get it or not? Please reply, i'd really appreciate it x x x

I have 2gb and I use it for social networking andYouTube a lot and it's more than enough. If you're not watching videos and only use it for twitter and Facebook you have nothing to worry about

Assuming you get 1GB a month, you'll only ever run out of data when streaming videos/tethering a lot.
On my Android phone, I tether and generally use mobile internet a lot and according to the data monitor, I've only used 219.6MB since February 1st so for your usage, 1GB is perfect.

The iPhones no longer come with unlimited. Because dad got it for you, no doubt he purchased the family plan and set it to the lowest settings between you and him and whoever else. 1GB will run out if you are not in the home in a matter of days.

If you visit the link below, you can find out your estimations. But you have to limit yourself severely. Like no movies or video game downloads.

Verizon I think is a little severe on the calculations though. They say I can watch 10 minutes of videos every day for 31 days and burn through 1.5 GBs.