Our Himalayan Puddy got blocked the one year--he was 8 years old at the time. Initially the vet drained his bladder and then sent him home with the special food which was supposed to cure the problem. Puddy wouldn't eat the special food...we had a total of 4 trips to the vet to get his bladder drained--usually after hours calls, because he'd be good through the day, and then in the evening would start trying to pee & then couldn't & would start crying. Vet was annoyed with the late night calls, I was annoyed with the growing vet bill and by the fact that I kept telling them to do the surgery and they kept refusing. They (two young lady vets at the clinic we used) kept insisting that the surgery had side effects too, and shouldn't be done just willy - nilly.
Finally the one day I lost my temper and told them that either they were to do the surgery or put the cat to sleep. I pointed out that all they do is drain his bladder and insist that the special food will fix him up--only he won't eat the special food and so it cannot help him, plus he was getting very thin...so operate, or else. They did the surgery and he was perfectly fine after that. If they'd operated in the first place my bill would have been $300 instead of the $1000+ that it was!! I have not taken an animal to that clinic since, and will not as long as either one of those vets is running the place.
Sadly, Puddy lived only 6 months after that. He became ill with the dry form of FIP and had to be euthanized. In hindsight, I believe that it was FIP that caused him to start blocking up--FIP can cause that. Many cats that block up start doing it at a young age--and most times it is indoor cats that have the problem. Puddy, in spite of being a fancy Himalayan, was outdoors more than he was indoors--he loved being outside. Possibly the stress of the repeated blockages could have triggered the FIP to become active--another reason to support doing the surgery early, as the surgery would have been less traumatic than the repeated blockages were--but I truly believe it was the FIP that caused his problems in the first place, and at the time he first blocked up he was already on borrowed time.
So, in view of my experience with Puddy, if we ever have another cat that blocks up, I will insist on having the surgery done ASAP--I am not going to mess around with special foods and hoping they work, and I'm not paying for having a bladder drained--I will have the surgery done & be finished with it.