I don't know if I missed this in my search or not, but when do you recommend to start brushing a puppy?

As soon as you can. Just to get them used to being brushed and handled. If you wait, they could be a real pain to brush later on.

I agree, definitely start getting them used to being handled and brushed. Just quick few minute sessions in the beginning, and make sure you get used to doing their nails. Dogs who don't have their feet/nails handled in the beginning can be a real pain to do later in life. Cheyenne and Rodeo I worked on since they got here and they're the best. They just lay there and don't move. The others have gotten to that point with time but it would have been easier if they were introduced to it while young.

Hmm, I wonder what I did wrong. I did all those things consistently when he was a pup and he only tolerated being brushed and his feet handled. The last couple of years he's been more of a PITA! Maybe 'cause he's older and crankier?

Don't forget to handle his ears. Rub them as much as possible. Also makes it a lot easier to clean/check his ears.

I started runing a brush over Cooter once a day for 2-3 minutes, picking up his paws, handling his ears, etc. When he was 6 months old he went to the Groomers for the first time and has gone regularly every 2-3 months since.