My map is almost, just about, done... I think. I haven't done any portaling at all and there's no lag at all.  How important is portaling?

Well, it certainly improved my map's preformance. But i guess it also depends on the size and design of the map, and the efficiency of the portal's you make.. For bigger map's i would certainly recommend it, on the other hand i think the majorrity of the mappers out there doesn't add portals or even knows what they are.. Don't know if you have seen these tut's but they are quite great, and explain everything very well! Guess the rest is up to yourself to make a descision upon, size, preformance, detail etc...  http://www.youtube.com/watch?v=E_yE56jP2tY#ws

Alright thanks.  Ill check it out.

heavy detailed maps with a lot of fx running at the same time need portals,
a boxy map with 0 detail doesnt lol but it helps the most on pc with poor graphics cards
that wont be able to handle the same amount of tris as a pc with an nvidia or amd cards.