It's a little like finding someone to work on your car. If you know a little about cars, you're in a better position to evaluate the quality of whatever work you have done, which, if it's good, will confer a sense of trust in that repairperson going forward. If you know nothing about cars, you can only rely on the recommendations of others, or online reviews.
Same with guitars.
But the answer is not (IMO) to never have your car -- or your guitar -- evaluated and repaired, if it needs repair. If you feel like you haven't found the right person yet, I recommend you shake the bushes till you find the right person.
Recommending that you have the loose braces on your guitar repaired is NOT indicative of your repairperson being persnickety. Loose braces are a serious problem which, if left unaddressed, can lead to further damage and possibly the need for a more expensive repair down the road.
If you're not sure whether your repairperson is being straight with you, ask to see pictures of the feeler gauges under the loose braces, or ask him / her to show you. Or read what others have said about the repairperson to get a sense of their reputation.