tools: Philips #2, zip ties, cutters, 99% isopropyl electronics alcohol, cans of air, multimeter for desktops, you will need the tiny Philips screwdrivers for laptops.
support wise: many computer manuals (good for laptops) service manuals can be found here : https://www.manualslib.com/
Software wise, download the ISO of creator Windows 10 , burn it to 16GB USB with https://rufus.akeo.ie/ and keep it handy to upgrade Window 7/8 boxes that still want the free upgrade done, as well as reformatting drives utility. (why 16GB, because I always add other utils on the USB such as CCleaner, defraggler etc)
also a nice quick load of utils on a blank pc is the use of https://ninite.com/
Hardware: get a USB HDD stand to make laptop...