Two weeks ago I came back to Canada from my 1month training stint in California. I didn't bring the powercranks down because of travel.  Since I have been back I have been on them a few times (indoor) and there are as hard as ever. I think the key is to use them atleast 2 times a week.  I am back in California in 1 week.  Once I am back in April - the use of the PCs will increase for the racing season! I hope all the work pays off!