ive got a big van and its full three large stacka crates of plastic ,pan cons.enough 4 inch fittings to do a stack and a few extra like street bends,mf 45s
six f and e tanks with push fits, valves ,rad valve trvs, 28 mm fittings,traps macalpine fitting ,combined wastes,loads of bins full of copper fittings flexis couple of flush pipes box of gas stuff the list is endless i hate having to go out to get stuff
its realy gonna depend on what work your doing i alternate between jobbing installs and repair so loads of stuffanother plumber i know has one box of tools and a box of fittings but he does mostly labour only and everything is supp;ied on the job
my stock has been built up over years constantly changing
always buy extras when you need some thing and it soon builds up that way you get a stock of what your using