I've been running my own private server for some time now and I know the basic ins and outs of the whole thing.

I run on Bukkit and play host to only 6 people total (including myself.

Everything is running on a server PC (not the one that I play on) with 4 gigs of ram and a dual-core 3.2 mhz CPU.

So, question to those more experienced on the whole issue. Is there any reason for me to limit the scope of my maps? I've seen larger servers limit the size at -3000 3000 in both directions, but is there any reason for me to do so as a tiny server hosting only a few people?

Along the same line - does creating multiple worlds with multiverse have a cumulative effect on CPU and memory use, or does it somehow add up to more than the sum of all parts? The reason I ask is because I tend to create new worlds as new landscape features come out and connect them via Stargate - that way we can experience the new stuff, but the buildings in our old world remain intact.

TL;DR - On a small server of 6 people, should I put limits on the distance my users can explore, or is it a nonissue?