I'm just wondering. The whole, 150 day limit is sort of off putting.
Thank you.

It has the limit. However, 150 days feels like forever, and as long as you don't stand around and do nothing, you should be perfectly fine.
And I believe once you complete the first two big missions you're free to do what ever you want (as much as that is.) forever.

It has the limit.
150 days is definitely enough time to complete the main story and all the sidequests, but you definitely don't have time to dawdle. And the "first two big missions" consume the entire game; once they're done, the game is over, and you cannot continue playing.

You can use the End game Mod to continue playing after you complete the quests. [url=]http://www.gog.com/en/forum/Fallout_Series/fallout_mods[/url] So if you focus on the main quests and complete the game you can go back and do sidequests explore etc after.

yes, it has the initial 150 days, but after you get the water chip, it gives you something like 500 years.

13 years, but it should normally be largely enough.

Thanks!
Also, are mods usable if I purchase the game off of here?
Sorry for the sort of stupid questions, I've never really been a big PC gamer.

http://www.gog.com/en/forum/Fallout_Series/fallout_mods/_/1
I didn't really look at the page much, but all those mods were all tested. There are some stickies on the forums if you look for the later games, too.

Gog games are no different then retail copys when it comes to installing patches or mods for them. So it shouldn't be a problem at all.