Continual low-level leg muscle aching?

[VRE]

Is this normal?

I do ride a lot: for the last 3 years I've been averaging at least 15,000km per year, and this year's the biggest yet, with my monthly average just over 1,500km. I have a 30km commute (1-way), and the round-trip commute has approx. 900m climbing, so plenty of hills.

I try to drink a reasonable amount of water each day, particularly just before each commute. I've had this continual low-level muscle pains in my legs for a long time now, and I've actually become used to it. But is it normal for this level of cycling activity, and if not, any suggestions on what I can do to reduce or stop it?

[toolonglegs]

If you are doing hard km's then yes... But to what degree I suppose. Obviously you are not injured as you have been doing it for 3 years.
As long as it is muscle rebuild pain and not tight hips / tendon pain.
Maybe checking your diet - protein intake enough?. Your getting enough rest?. Your bike position is good?. Maybe a bit of stretching to loosen up the muscles.
There could Be a lot of causes and a lot of remedies.

[nescius]

Without any real details to go on, I would suggest these things:
1. Incorporate some rest - Ride two days easy, small chainring the whole way, both ways.
2. Start a regular stretching/massage program
3. Make sure you are eating and drinking enough and that it's the right stuff, see a dietician or someone who can tell you what you should be eating.
4. How is your bike fit? Maybe some tweaking could help things (unlikely if you have been doing more than 300km/week for the last 3 years, but always worth considering)

edit: basically the same advice as TLL suggested

[Reman]

You should also take a long break from riding every now and then. Say 2 weeks every 6 months.

Otherwise those pains can become niggling injuries which can turn into something major.