Like you, I'm not running for a race, or to seriously train. I don't usually use a watch (I'll strap on my dh's garmin to do a long run, though).
Currently, I'm running about 20 a week. It's comfortable, and my goal is consistency. Sometimes I'll do a couple less, sometimes a couple more. With 20 mpw, 4 days is sufficient. usually it'll look like something like this...
7
r
4
4
r
5
r
Great question. I'm interested in hearing what others are doing.

I mostly run on trails and rarely race. When I do race, I approach it like a group run, not a competitive effort. Also, I have a tendency to get injured if I don't cross-train. Typical week, taken from Maffetone:

M -- 45 minutes, stationary bike
T -- 45-60 minutes, run
W -- 45-60 minutes, run
T -- 45 minutes, stationary bike
F -- 45-60 minutes, run
S -- off
S -- 75-180 minutes, run

All of this is down below my MAF heart rate -- which I find keeps me from overdoing anything and risking injury.

I run two marathons a year and that's it. Most of the time, I just run without any specific training goal. I do the marathons to force me to do runs longer than 13.1 miles. I run half marathon distance once a week.