I would say do not start a new World until you are doing most of the things possible in the World you are in. I started several early on. and gradually had to delet them after spending a lot of time working them. mainly because it became, over time ,way too much work. Deleting cities ispent many hundreds of hours on was difficult. but had to be done. more things became possible, in Guilds and the game all around, I just could not do them all. I still play three Worlds and it is a lot of extra work all the time. And I thought it was easy at first too.. Get to the point you are fully committes to GbG in the one World in a good Guild.. and then see if you say more is better.