I have ;
2 novak 13.5's
1novak ss5800 that has the sintered upgrade
1 novak 8.5
All of them run like new after over a year of use.We have a track at our house so the 17.5's and the 13.5's get used ALOT.
I gear mine using a temp gun.I never run them over 135* .As for maitenance , I clean and oil the bearings every 10 runs.I dont use motor spray on the front bearings though.I use wd 40 after taking the front end bell off,then oil with bearing oil.Then blow out the motor using compressed air. I have never had an issue with the rear bearing since its pretty much sealed, so I just lube it with a couple drops of oil.
so far doing things this way I have had no issues out of any of the 8 BL motors I run, and all of them still perform super.