is unity only a 30 day trial?

I got unity from here: http://unity3d.com/unity/download/. i know the pro assets will expire after 30 days, but what about the standard program and my projects? can i still use that stuff and create new projects and stuff? thanks!

Yes. You have a 30 day trial for the pro version. When that trial runs out, you still have a license for the free version which you can use indefinitely.

Unity is completely free and can be used beyond the pro trial length. After the Pro trial expires, you should be able to continue to use the program you have installed, with nothing else required.

Yes, the only difference will be is such effects as realtime shadows etc will no longer work in your game anymore.

Well, “only” is relative. I only had the trial for 3 days before I was sold!

The Profiler alone is worth at least half the cost. I regularly double my game’s fps (I.e. back to 60 when a mistake knocks it down to 30 or worse) by using it to pinpoint blow-outs.

Realtime shadows are simply essential for a large class of games, though of course you can live without them.

RenderTextures become more and more valuable as you find uses for them. Sure, they are big-ticket when you want realtime reflections and stuff, but for example in my current project, I render all the GUI icons dynamically from existing game assets, making for a very nice workflow (plus a little reduction in download… I need lots of hi-res item icons).