We have new microwave and wall oven to be put in tall cabinet, DW, and gas cooktop. We (meaning mostly DH with help as needed from me) are installing everything except gas cooktop ourselves in our original cabinets from 22 years ago. We are paying someone to install the gas cooktop.
What a job it has turned out to be---especially the wall oven and microwave. We have 27" cabinets, and they both barely fit--we had to enlarge the cutouts for both, as well as make a lot of other adjustments to fit them in.
The wall oven was especially hard---first, that thing is HEAVY---I almost couldn't help DH to move it, and I was scared I was going to drop it. Then we had to cut out much larger hole---all that was left was the cabinet frame---for the oven. (The opening had to be cut twice, actually, because DH misread or mismeasured the first time.) Then, when we thought we could finally slide it in, there were tiny screws sticking out slightly toward the front which made it impossible to get it in the last few inches .... so, mark where the screws were on the side of the cabinet, slide it out AGAIN, and use a round file to chisel out an indentation in the cabinet frame to allow the oven to slide in.
Victory at last! But wait, it still won't go---the oven is so deep that the conduit containing the electrical wires doesn't fit behind the oven. So, after some discussion about what to do, DH expanded the small opening in the back of the cabinet at the bottom to extend all the way up--there was enough room to lay the conduit over the top of the oven. However, the entry point for the wires to come into the oven was on the side, where there isn't ANY room to get the wires through. So we punch a hole in the top cover of the oven and bring the wires through that way. Whew!
Finally, after being up two very late nights working on these, all appliances are in and working. Who knew it would be this challenging?