I've switched to light weight battery op hand clippers, small battery op chain saw, reciprocating saw-battery op. Also use a garden tractor and a large John deer tractor with scooper and to mow the pastures and various other chores plus hauling.
I have several acres and a pretty good size pasture to manage, horses, moles, voles, gophers, raccoons, bobcats, bears… just keeping cameras around the property is a huge help.
Also using 'Mindfulness' before tackling any project is absolutely the most important step. Think ahead plan out projects …like using leverage with other objects to move heavy objects instead of lifting.
Wearing elastic supports for back, knees and shoulders. Dressing for gardening isn't just a pair of gloves any more.
Also been downsizing the garden lil by lil. Keeping the garden with in easy manageable spaces .
Keep the core muscles strong and understanding my personal limitations is key to successful gardening as we age. Add always drink a protein shake to help maintain energy for a lil better endurance rate.