I am 67 years old now. When I was about 50, I started having trouble with knee pain. So... I decided that every time I need to get in a bottom drawer, pick up something off the floor or reach into a bottom cupboard, I would squat all the way down. Before long, that cured my knee trouble and I am still doing that.
Fast forward to last year when we moved into our trailer. This little house is considerably smaller than the old house we lived in, and before long I noticed that I need to work a little harder to get enough exercise. To the squatting routine, I've added something else. When I need to bend and reach, I always bend and reach "harder" than I would need to, in order to complete the task. When I bend over at the waist to blow dry my hair, I bed way down so it stretches the back of my legs. It is kind of hard to describe, but I think you probably get the idea.
It's a small change, but has made a world of difference in my flexibility. Along with that, instead of walking on the road for exercise, most of the time I walk in the woods. It is uneven ground and up and down hills. That has improved my balance. After falling 3 times in two days, I decided it was time to do something about it.
It's amazing to me how working these small changes into my routine has improved my health. These things don't take any longer. Please think about what you could do similar. You will probably be happy with the results!