How long is your recovey between leg days?

I do legs Mondays and Thursdays.

if you are talking about running, I use a 9 day schedule, and never run within 2 days of a long or hard run. Quality vs quantity, plus the older you get the more time it takes to recover, lol

Depends on what you mean by "leg day" and what you mean by "recovery" LOL

I squat at 85% of my training max (about 75% of true 1RM) on Monday, 90% on Wednesday and 95% on Friday and also run 3-5 miles on Tuesday and Thursday then either do a long run of 6-10 miles on the weekend or if I'm playing soccer at the time, I'll have a game where I'm running for 1.5 hrs. I also usually DL on Fridays, so "true" recovery is only a day a week. I prefer to look at my running as "active recovery" though

I do deadlift training on monday usually involving some leg assisitance work
Squat thursdays and saturdays.

Depending if you are reffering to weight training, muscle protein synthesis to my knowledge the latest studies have show is only active for 24-48 hours after a training session. So the best thing to do is to keep that stimulated as much as you can handle. I've done as many as 5 lowerbody workouts in a training week.
Mind I train submaximally meaning I dont max out every session I use loads that difficult but managable in the 70-85% range for several reps and sets. The muscle wont be the actual issue. The issue with frequent training is soft tissue(tendons and ligaments) and the Central Nervous System.

I recommend no less than 2 "leg days" because it gives a good amount of muscular stimulation. If you feel you are recovering enough from the 2 you can begin to slowly over time build up to more but 2 leg days will get you very very far.
This is why 4 day upper lower type splits are the rage these days its a good managable balance of frequency and recovery.

Heavy squats Monday.
Back-off squats and DL on Thursday.

I'm in my 40's. I also have trouble getting enough sleep and am cutting at the moment.

Two total rest days gets me back to 80% after heavy deadlift, back squats and a 3-6 mile run. I need three days for complete recovery.

Up to 3 days for a major:
Legs, chest, back

However, What also becomes a factor when it comes to rest time is the intensity and program involved in each of the workouts

I do legs twice a week.
Wednesday - quads
Saturday - hamstrings

twice in 8 days three days rest always five sets each Squats, lunges, leg press, leg ext, stiff legged deadlifts leg curls. I do Box jumps 5 sets 8 reps 30 inches two days after legs day in my cross fit class.

Didn't think about biking for legs I bike everyday 9-11 miles every morning 5 min after I wake up- Its a 30 min ride just gets me going..

My program is full body so every day I workout is leg day...but I don't work out on consecutive days...there's always at least a day in between.

Of course, this is going to depend on your program and what kind of volume you're talking about...more volume = longer recovery time.

2 days.. I am in my late 40's and I run too.. so need extra recovery for me!

Typically every other day. Though I've done everyday for a month a couple times for form work.

I'm Monday/Friday lower body, Sunday/Wednesday upper body. All four are heavy lifting sessions though!

Something not addressed thus far has to do with how many leg exercises are involved during your leg day. If you do legs twice per week but only 1-2 leg exercises per session, it's a far cry different from doing legs once per week but hammering out 5-6 leg exercises in that single workout.

I'm in my 50's so it's 2 days.

Once a week. But then again, I'm not looking to increase size or significantly improve my strength. I train them once a week (like every other body part) to maintain my current muscle mass.

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