Hi all!
I would like your opinion about which is more important: hills, speed, or distance. I am currently riding about 20 miles a day/four times a week. I would like to improve my biking and endurance overall.

I ride ~20 miles at 14-15mph, and that gives me a good workout. (Hills KILL me!) So, any suggestions on what area I should focus on?

Thanks for your input and opinions!