I'm 55 and had a dodgy elbow, what works for me is:
1. Lightest equipment:
Xtreme 22, with xtreme brushes, I've added 50m of gardiners reinforced pole hose on my main reel (easy to use and reel in), working out the side of my van (so it's usually a straight run).
2. Easy, small houses.
I try and avoid big connies that you have to reach over, or large extensions that need step ladders. Nice, simple in and out work for me. I am even thinking of offering front only on terraced, or specifically targeting bungalows.
3. Stress, keep it to a minimum.
I can't be bothered with: first floor flats (unless I can get the block!), custies with dogs, people who no speaky English, going through terraced houses, or drive round the back, rude people, idiots, bad payers, people who take 10 mins to answer the door, or pick up the phone, etc etc etc!
In fact when someone calls me with a 3 bed semi, no connie, and they're normal...it's like a breath of fresh air.
I shall try pilates soon as well.