Its hard to say, if its a reputable shop its likely money well spent.
several years ago I had a transmission rebuilt in a service vehichle, Itw as in for an oil change @ one of those no appointment neccecary joints, the guy came over to me with the transmission dipstick in his hand, he said the fluid had gone dark & had a bad smell to it, that it should be changed, I said, Gee, funny, I just had the transmission rebuilt, I'll have to go back to them and see what they say, body language told me that he was BSing me.
This same place tried to sell me an air filter because it was ripped, I demanded to see the manager because it was a new air filter, and the only way it could have got ripped was by them pulling it out of the housing (very awkward), I demanded a new filter to replace the one they had damaged, and the manager agreed!
On that same note, I had the same vehichle in for a tune up, the mechanic (that I've used for 30 yrs) called me & said I have a fuel injection problem, he'd like for me to come see what hes talking about. I have full trust in him but made my way to see what he was talking about, he showed me what the one injector was doing compared to the the other 7, I could see first hand there was a problem, a few hundred dollar tune up became almost a grand, but had I not adreesed the injector problem, I would have cooked the engine.
I am a firm believer in perventitive maintenance, but you also have to be wise, and be careful you're not getting ripped off!