If done properly an annual check will not do any harm whatsoever, and it could safe you a whole world of hurt.
The problems usualy start when a very large job has to be carried out and it disturbs a bit of shoddy workmanship in the distant past.
Recently I had the wing off a PA28R to change the walkway skin but during the refitting of the wing we had big electrical issues that resulted from poor workmanship carried out six or seven years back. This cost the customer about 6 hours labour to fix.
But in the long run that is cheaper than having the aircraft go "tech" in the south of France.