VLAN Implementation Question

Just wanted to get a few answers in regards to VLAN implementation.

How many of you -
1.) Have successfully implemented VLAN's into a production environment (e.g. placed servers, production, printers, etc. on separate VLAN's)?
2.) How much of a pain is it to do this? If you are on a 192.168.1.x subnet, do you have to re-IP all of your printers, switches, etc. This sounds like a lot of work – especially since re-IP’ing domain controllers is a royal pain.
3.) Have you seen much of a performance increase when implementing VLAN’s (i.e. chatty protocols and broadcasts?)
4.) Any other VLAN advice would be useful

Thanks!