What do you do when the experience at one of your favorite places goes sour?
For instance, we used to have a favorite suburban sushi restaurant that we would go to every 3-4 weeks, spending $40-50 each time (and this was 4-5 years ago).
2 problems arose:
It got very popular with families, who would let their children run around and shriek, and there was turnover in the wait staff, resulting in a crew who got orders wrong and didn't keep water glasses full.
We REALLY liked the joint, still haven't adequately replaced it in our rotation. Was there something we could have done? The owner was always on site, I was tempted the last few times to tell him that we were just about done going there, due to the above issues, but I'm not usually one to raise a fuss, I just move on. But I do miss this place.
My approach would depend on what the problem was.
If the issue were with the food or the service, I would probably write to the owner to let them know that we were regular customers, but that we were reconsidering this due to the change in menu/surly service/decrease in food quality or whatever the problem was. Then I'd wait a bit and give them another chance to see what they can do - keeping stricter watch on their staff, for example.
As far as ambience and the customer base goes, though, I'm not sure I'd bother, because I can't really see them fixing the problem. They aren't going to turn away families with small children (or groups of teenagers, or office parties, to give other groups that can be problems) at the door, and asking the restaurant to police the behaviour of their customers is pretty tricky, and logistically difficult for them to do.
About a year ago I sent an e-mail to a restaurant we used to frequent at least once every month or two. It was not inexpensive and we saved it for special evenings. The food I got tasted off and the waitress was not very helpful. We really liked to go to this restaurant and didn't want others to have the awful experience I did. So I let the owner know how much we liked it , what happened etc, etc. He was so rude to me in his return e-mail that we have not and will not return. I think it is important to let the owner know and if they are rude then there is just more reason not to go back.
we used to like a place locally with great food, menu changed fairly frequently but with old favorites still on the menu, then suddenly the standard slipped, food became tasteless, favorites were gone and the menu was the same for over 6 months.
Gave it a couple more tries with no changes and finally gave up going.
I think it's appropriate to discuss systemic service issues with the owner of a place you like. Most will appreciate the feedback, especially if it's in the context of your love for the place, not (as it sometimes is) a solicitation of compensation.
I'm not sure how you deal with the families-with-unruly-kids issue. I agree that that can ruin a place for me, but I'm not sure what an owner can do about it. (And it's a can of worms on Chowhound, practically a taboo subject.)