My rules of thumb:

If I ride a bit, OK ride.
If I ride as much as I can, good ride.
If I ride more than I thought I could, sweet ride.
If I get back, walk in, fall on the couch and my wife finds me in a coma 3 hours later, kick @$$ ride!
If I walk out, look at my bike, go back in and plop down on the couch for some TV, bad ride (unless I'm watching the TdF).

The only bad ride is the one you passed on

That said, if you're not "nicely tired", you need to do more. Sounds like you need to do more. OTOH, how many other 45 yo's you know doing 10 miles several times a week?