Trimmer Engine Maintenance

I just bought a string trimmer with a 4 stroke engine. Reading the owner's manual told me that it requires an inspection of the rocker clearances every 25 hours. The process requires a feeler gauge, which I don't have, and a torque wrench of some sort to reassemble the engine cover.
While I'm sure I can perform this maintenance, I'm a bit irked that these tasks are required for this simple device. I've never had to do this stuff for the 4-stroke lawn mower engines that I've owned, so I'm thinking that this trimmer is poorly designed in some fashion that requires periodic disassembly.
Are ALL four stroke engines of this size going to require me to do these inspections, or did I just buy an inferior model? (Troy-Bilt)
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