I haven't been doing a lot of exercises for some time because I have been busy with housework. However, recently, when I went to YouTube for my favorite workout videos and tried those quick 20 or 30 minute workouts, to my surprise I found that I had not lost my stamina. Doing those YouTube fitness workouts for 20 minutes or so did not leave me breathless as I had thought it would since I had not been very diligent with my workouts.
I found that I could do them easily as before. Thanks to my daily workouts with my mop and my pail. Actually, I use the mop and pail only once or twice a week. ;) I think its carrying the children's 4 heavy bags to and from the car and up and down the stairs that contributes. (No, I don't have 4 kids, but their school bag load is so crazy, they each carry not one but TWO heavy bags to school daily).
So, if you're a SAHM like me and you don't belong to an expensive gym, fret not. You can still have your workout in your own personal gym with your own personal trainer (the mop, pail of water and heavy school bags). Exercise is free. You can do it anytime.