I’ve had my 450c for about 13 years now and it’s been in multiple vehicles with countless cycles and zero issues 
Just pulled it out of my Land Cruiser (replaced it with a 444c dual pack) and I plan on putting it in my XB with a pair of K bells 
I figure now would be the best time to treat it to a set of brushes, but I’m just curious as to how often they need to be replaced 
OK, I sized up where I might be installing the 450c on my beater and because it’s a tight space with minimal access, I took it upon myself to pull the brush cap and see what was left in there.
I was expecting to see bare nubs, but they looked to be in excellent condition for their age and use :eek:
Cleaned up some of the dust, put a little lube on the bearing and put it back to gether.
Probably be good for another 13 years
My 7yo 400C’s brushes were about the same or a little shorter than those.