All US aircraft are required to undergo a comprehensive inspection every year. My own little airplane is no exception, and while many aircraft owners dread “the annual”, I look forward to this as an excuse to take some time off from the job that pays for all this and spend quality time with my torque wrenches, magneto synchronizer, compression tester, inspection mirrors, and other tools. I also like keeping my airplane well-maintained, and knowing that we have no secrets from each other.
So here’s what a small airplane looks like half way through an annual inspection:

The interior also gets opened up for inspection:

Which all means that right now I have something that looks more like a collection of airplane parts, rather than an airplane:

A lot of servicing also gets done at the same time. As long as we’re going to open up the oil filter and take an oil sample for analysis to look for signs of something coming undone in the engine, might as well put a fresh new filter on, change the oil, and clean the spark plugs, lubricate all the controls, etc… Really, the actual inspecting can be done in a small number of hours. It’s all the disassembly, servicing, reassembly, and checkout that takes days.