If they have been a vendor over a month(or around that...maybe 2 or 3 but I am pretty sure a month) and have 35+ feed backs then they can ask you to or even require you to. You don't have to of course but they also do not have to vend to you. As there are over a thousand post on here NOT to FE...There are some rare instances and some vendors that you have to if you want to do business. There is usually always an alternate vendor you can deal with. I would suggest you should never finalize early. Good luck