customary tip

hi everyone,

what is the customary to give when tipping the vendors?

i found this on theknot.com:
http://wedding.theknot.com/wedding-planning/wedding-budget/articles/wedding-vendor-tipping-cheat-sheet.aspx

but i'm not sure if this is what the norm is... and i'm also not sure if it's what the vendors would expect as well...

help!

thanks ladies!!!

ahhh 10 more days until our wedding!!