There's no real limit, other than flight time. It can be very challenging for the 3 FA's to serve all 100+ pax on some of our shorter flights, it also depends on what everyone orders (mixed drinks, hot chocolate, tea and coffee take a wee bit longer).

Most pax don't really realize (nor do I expect them to) the time it can take to set up the galley, get orders, serve, cleanup, restock, do trash and settle/close out liquor kits and other paperwork and be seated for landing! That's NOT to say I don't enjoy my job, I LUV it! Just a little insight into our world!

As long as you don't ask for FA for a refill before he/she has even finished serving the other pax their first round and you're polite about it then I don't see where there's a problem! When people are nice I'm more than happy to do anything to KEEP them happy! I'm glad at WN we're able to provide, or attempt to do so (sometimes I don't finish) full service on almost ALL flights! It's another benefit of not having carts... they're not allowed out below 10K feet and if we at WN waited till 10K to start service on some routes (RSW-MCO, HOU-AUS, BUR-LAS etc etc) then we'd never finish!

Rarely have a had a pax get mad at me for not finishing... and I was sweating... I thought that was good proof I'd at least tried!