do you ride by time or miles?

[Batbike]

I can rememebr back when I started reading a Gref le Mond book , an he recommend traing by time instead of miles, reason being that as you got better, if went by miles, your training time would decrease.

If I understand correctly, if you go by time you will increase your miles in the same amount of time as your fitness improves?

Makes me wonder if that is really true -- I guess you would have to do the same route on multiple days to determine that. Would you also monitor your HR to check fitness?

... questions, questions, questions -- I ALWAYS seem to have questions!