Any question answered...

"overdoing it" is dependent on the person, if they are sufferring from severe fatigue, hormonal/emotional problems, injuries, deterioration of physical ability and nightmares. Then you could say they were overdoing it.

Sanddancer just has tired legs. This is totally normal and hardly an inconvenience. Dropping out days of riding will not necessarily reduce this as they are clearly well adapted to riding a lot. Riding less might just 'detrain' them.

I would recommend, more food (good stuff) and hot baths. Massages may help but unless you have someone to do it for free, or you have a specific knot/cramp etc, I would not bother. Also sleep, lots of sleep.

If you are asking from a training perspective and are concerned about optimising your performance. You may want to start periodising your riding. Introducing recovery periods where you go easy, so you can go much harder than usual at other times - to beat your own distance/endurance and speed records.

If you are always tired from commuting/junk miles, you may maintain a decent tolerance for mileage. But you will never get to really push yourself to be faster.

The sleep thing could be an issue. I'm working two jobs and also doing an Open Uni degree so 4 hours is about the most I can expect. This is something I hope to change in the next couple of months though.

I wasn't really thinking about doing them for a performance benfit, though that would be a nice bonus. It really came about because there was an offer on at a local place and I thought it may just make me more comfortable. Just didn't want to spend the money if the benefit from a session was only going last until the next ride.

I think from a performance point of view, the junk miles observation is spot on. I find these days I find it hard to put in really intense efforts when riding and it's always my legs that give out first, never getting that heart racing, feeling like you're about to puke out your lungs sensation. More like a struggle against fatige than against the effort, if that makes sense.

Think it's time to start working out a structured training/riding plan...