Contributors to this thread:
who uses tree saddle am I to old 
Am I to old to use one  ? I have always used a climber.
There was a retirement age Asian man that lived down the street from me for a while. It took him at least 2 weeks to cut down a 60 to 80 foot hardwood tree in his yard. I drove past every day and couldn't wait to see if he was wedged into a V with a nylon rope tied around his waist like a belt...NOT how I would do it, but he used what he had...a ladder, rope, and a hand saw. If you set yourself up for success, and feel safe, go for it. SRT (single rope technology) climbing systems are very safe and you have the flexibility to add redundancy to your system to increase safety. Check out saddlehunter.com and see if it's for you. Lots of climbing methods out there.
If you can climb a ladder, you can hunt from a saddle. As far as effort required, it is simple with a linemans belt to hang sticks. Learn to trust your ropes and lean into them and you can do it without ever breaking a sweat. Good luck and God Bless
Once you get the hang of it they are safer than tree stands and better shoot-ability.
I am 70, yesterday. I tried one, demonstration at a farm, this winter, on poles in the barn. I had no issues. I have had work experience with ropes, so it was easy. I just did not care for the system, but you can use it, like anyone else. Their are pri and con, so you will sort it out ..good luck
Only you can say if you can or can't. 75 isn't exactly a one size fits all age.
Just offhand, I would say if you can hang a "trad" stand by yourself a saddle shouldn't be any issue. As stated above, really not a big difference in the mechanics of a linesman belt and a saddle. But you are the one that needs to make that call.