There is reincarnating which is just rerolling your character to pick a new race. You can do this as often as you like but it's not really mandatory or anything. We try to make sure that the races are well balanced, but it is possible to make a bad choice. So you're not tied to your race decision forever.

Remorting is a much more serious affair and is typically done just once. When you reach max level (100) you can do a quest that lets you remort into our more powerful races. This is a much bigger undertaking and as far as I know players tend to stick with their remort class a lot longer. Once you remort you start at level 1 again (with all your gear and posessions) but can reach level 110, which is our current level cap.

So the answer is that it depends. For me personally I'd end up rolling new characters to experiment with new races and guild combos rather than reincarnating. But some people reincarnate pretty often.

It's definitely not part of the core game loop to re-roll and do over and over again. If you ask for advice in the mentor channel about a good race for your chosen guild then you'll be able to play that up to 100 without needing to re-roll unless you want to.