Full Worlds
Aside from WvW, you can do anything you want with your friend even if you’re not on the same server. Just be in the same region (NA / EU).
Tarnished Coast
just invite him to a party and reload the area you are in. No matter what world you are on you should still be able to do PVE together. WvW not so much.
Sythern the Warlock: Human Necromancer| Lithia the Shadow: Human Theif
Lumata: Asura Mesmer|Arion of HonorHall: Human Guardian |Abigail the Tamer: Norn Hunter
Here is a post from Gaile about server population, albeit a bit dated.
As mentioned above, with the recent changes the only thing servers are used for is to determine allegiances in WvW. Aside from that, you can do most everything with anyone from the same region and benefit from guild buffs regardless of what server you are in (again, as long as you’re in the same region).
How often do full worlds open up?
Full servers are full until a certain amount of people transfer off of them. Unless you get lucky, you won’t see a full server not full. For example, I was guesting every day for several months at random times and only saw Blackgate drop to high once for a few hours.
Once in a while however, ArenaNet updates the population counts, causing all the servers to drop down a population rank, where full becomes high and so on. When this happens the regular full servers usually become full again within a few days. This used to be done randomly once or twice a year, but now they seem to do it just before the start of a WvW season. They just did it last month for example.
How often do full worlds open up?
I just started playing during the free trial, and then purchased the game.
Friend that I want to do stuff with is on a full world.
Feel like I wasted money if I can’t get on the same one.
if they’re top tier they open up never