FI and I managed to hand address, stuff, stamp and seal all the invitations in one night! It was actually not as painful a process as I imagined. We didn't have very complicated invititations -- just a flat invitation, response card and card directing people to our wedding website. No folding or ribbon tying or anything required. DEFINITELY the way to go -- so fast and easy!
I was nervous about hand writing the addresses, but they came out fine. Nothing fancy, but very neat and readable. FI used cardboard to make a little template for me -- I slid the envelope into part of a carboard box, then put a little cardboard cutout on top. The cutout had a hole where I needed to write the address, so every address ended up centered without me having to measure or guess. Hard to explain, but a genius move on FI's part! And FI did the stuffing, stamping and sealing.
I'm mailing them out on Wednesday -- so excited!! It's a big weight to have those done.