missing stray/feral cat

Hello, this is my second post on this forum. For the past year, I've been feeding a stray/feral cat named Max. I was able to take him to the vet about a month ago to get neutered. He didn't show up for a few days after that but fortunately he came back about a week  later. Lately, Max started hanging around my backyard more often than before. He would spend hours there and I could tell that he was starting to feel comfortable. On September 25th,  Max didn't show up on regular feeding time. So I told myself to wait for a few days but it's the 27th now and he hasn't shown up. I am very, very worried because I feel that something might have happened to him. I don't see any signs of him at all. I've checked around my immediate neighborhood and still nothing. He's usually a very predictable cat. Also, I don't live in a cat friendly place- I always see runover cats/dogs/squirrels in my neighborhood on a monthly basis. My question is, is it normal for neutered cats to go missing longer than a few days? When should I start actively looking for him like sending out flyers etc? Should I wait a little longer? I am not really sure what to do. 

I would start looking right away. It may also be a good way to let your neighbors know that you are trying to take care of the cat so they do not call Animal Control to come get him. I would also check any local shelters just in case someone did call or trapped and took Max there. Check anywhere he may have gotten stuck. don't panic, just do it methodically and thoroughly. Check the shelters first maybe call and see if any cats were dropped off recently.

I hope you find him. and he is O.K.

Good luck.

Jim