by my house they say no problem with re useing mailers but they highly recommend the delivery confirmation. I think I stated before on TCB postal workers have told me they have SEEN people take the item out of the package and tell them "I never recieved it", they say there company depends on it!
This was confirmed by 2 different Post offices I use.
They say "track everything".
.65¢ delivery confirm is worth it to me
just passing along what i was told