I am not a professional eng builder by trade but I have been an auto tech since 1974 and learned all the basic eng building in training and working as a dealer tech all my life. I just build my own engines and some friends. I really like my telescoping gauges as I used them for valve spring height for years but did break down and get a valve spring height gauge this year. And have most of the basic tools of the Comp degree wheel , 3 dail indicators , piston height gauge , micrometers , cyl bore gauge , dail calipers and so on. My brother has his own machine shop so I have access to all his tools also like the valve spring tension tester and many others. I also broke down and bought a new Starrett dail caliper this year as the one I have that's digital seems to always have a dead battery every time grab it. But since I don't build engines everyday I guess that why. My brother also has a boring machine and all the valve equipment to do valve jobs but we have the stones which work fine for us and not the more modern cutters many use now. The one thing I like to question is how important is the rod bolt stretch gauge today since we just torqued rod bolts for so many years ? And I also still use a file in a vise to file ring gaps but if I did a lot of engines of course I would buy the tool. Ron