isolation valve insanity?

what do you think I have the taco zone valves coming off the supply manifold, and caleffi flowsetters going into the return manifold just upstream of the webstone purge valves. I also have webstone drain valves on the pumpflanges and boiler unions s/r outlets. Now im think what if i need to service the flow setters or taco zone valves [ i think the tacos are usually able to service by just control switch out] and wonder if i should add valves upstream of flowsetters and down stream of taco zone valves is that crazy or just first rate ? these caleffies have spring checks i worry might clog how likely is a taco zone valve brass portion likely to fail?