For me it often comes down to movement. Simple put, the more something moves, the more it breaks.
Three years ago now, I facd buying a very expensive implement for my bulldozer. I was not getting
wood out of the woods because I was constantly breaking cables. The problem was I needed to get logs up off the ground and on tires. I looked into home made log loaders, but there was a ton of movement, geometry, and hyraulics. In the end I decided that while insanely expensive, ($18,000), the difficult engineering had been done for me. I also decided I could fabricate new implements to go on it, and if needed, to rebuild it and make it stronger. BUT I had something to build off from.
I have never regretted the purchase even though most implments I make myself. I use the machine every day, and its long paid for itself...in the first 6 months I owned it in fact. I have since builta feller buncher head for it, an upside down woodsplitter head, grader blade, etc. It is the swiss army knife of Homesteading. And I use it for farm more that just logging. Everything from breaking the beads on farm
tractor tires, to putting siding on the house.