@Adrienne Donner I've found 2 things to be true when it comes to DIY.
1. Pros almost always work in pairs. Meaning one guy is measuring and cutting. One is installing. One is cutting and back rolling, the other is rolling. FIND A KNOWLEDGEABLE FRIEND with the same quality standards you have to help. Everything goes faster and pay your friend a couple bucks instead of a contractor.
2. Splicing in/patching etc usually causes more problems. Essentially it comes down to prep work. I did my first major drywall job and looking back my BIGGEST mistake was not taking down ALL the original drywall in the kitchen. Instead I tried to blend and shim 1/2" drywall to the previous 1/2" drywall plus 1/2" (give or take) plaster. I'm willing to bet any pro that would have quoted would not have touched that job without starting with new drywall throughout. In the end I caused myself more problems and sloppy mud because I was trying to blend uneven surfaces.
I would like to graduate from a lot of DIY jobs but I think having confidence in knowing that you are capable is a good thing. Know when to quit and what your time is worth though. A good contractor is worth their weight especially if sophisticated or expensive tools are involved.