I've been waiting for your thoughts on this. I LOVE doubles and even triples. I have completed T25 Alpha-Beta-Gamma multiple times, P90X3 once, just finished Insanity MAX:30, and have dabbled with 21-Day Fix, Asylum Vol I & II and original P90X workouts.
My wife has to be at work earlier than I do, so when she and I are done with the "scheduled" workout, I throw in another DVD. Usually I'll put in a workout from another program, or follow a resistance workout with cardio, or an upper body workout with Triometrics or other lower-body workout. Or sometimes for the bonus workout I'll just do 100 pullups, 200 pushups, yoga, or something else that takes the better part of a half hour.
Then after work, my buddy Rodrigo usually wants to put in a random T25 Beta or P90X3 DVD once we got through the scheduled Alpha and Beta calendars. He really needs the accountability of a workout buddy so I oblige. Rush hour traffic here is so bad that I might as well kill time before trying to drive home anyway. Morning workouts are the best but busting another one out after work always feels great.
The scheduled T25 Double Friday initially got me into it - I could really feel plateaus being busted. Admittedly, doing ANYTHING after a round of Max:30 took some mental discipline. The various half-hour BB workouts are a good library of content to mix and match on the "bonus rounds", as I call the 2nd and 3rd workout. If I miss the triple some days, I don't beat myself up and just hit it the next day - as long as I nail my primary and secondary workout I feel OK with it.
One Saturday last May, the guy who got me into BB workouts planned a huge BB fest before he moved away with his extensive BB library. We did the following circuit back to back with only the time to switch DVDs and eat bananas and pound BCAAs in between:
P90X3 Cold Start
T25 Speed 3.0
Insanity Vol II Power Legs
Insanity Asylum Vol II Ab Shredder
20 minute Run
Insanity Asylum Vol II Championship Sudden Death OT
Box squats 5 sets
Deadlift 5 sets
Insanity Asylum Vol I Strength
It took hours, but was a lot of fun and very educational. We had been training hard and were ready for the challenge. I guess I would do it again, but that Vol II stuff is HARD. I think it would be fun to do all of T25 Alpha back-to-back in one session, then try Beta and Gamma and maybe P90X3. The yoga and Pilates would be a nice recovery.
I agree 100% that you must sleep and eat in order to sustain this, and get your supplementation right. Fortunately, I enjoy sleeping and clean eating. However, I am delighted with the aesthetic and functional results of doing multiples, as well as the mental toughening. Heck, I'm 41!
MAX:30 Day 60 Progress photo from two weeks ago: