Think it's about time I chimed in too
I've had MS for nearly 20 years and I described a lot of it's effects on my 52 last year.
Mostly I use a crutch, sometimes my mobility scooter or manual wheelchair, and, very occasionally, nothing.
I have reduced power in my legs and when I get low down or lie down for a shot I can't get up again by myself. I can barely do stairs and going uphill or walking in the rough is out of the question. My balance is dodgy and I can't walk and look around at the same time as I walk like I'm drunk, weaving about the place. I can't stand still for long and when I do I have to brace myself somehow. This makes composing a picture very difficult sometimes. My lower arms and hands are weak and I've got arthritis there too so I can't hold the camera for long. I've also got a tremor, so add that to the poor balance and even IS doesn't help much.
The biggest impact however is fatigue. After only a couple of hours outside (or inside) taking photographs I've had it. Can't think straight, can't concentrate, feel nauseated and absolutely exhausted and have to stop. This means long shoots are out of the question and speculative ones are few and far between.
This last 3 months have been particularly hard as I've been having a relapse and have taken very few photographs. I said it was lack of mojo, but it's not really. I've got loads of ideas but no energy. A couple of times MrB and I went out especially (he carries my stuff, helps me up etc), got to where I wanted to go and had to turn around and come back as I wasn't up to it, and we're only talking 20 minutes away!
Even PP takes it's toll as mental activity is just as exhausting as physical activity. Some days I can spend a couple of hours on the computer and others, nada. And the problem with mental exhaustion is you don't realise you've overdone it until you stop and then you find out your body isn't working properly.
However, having MS is the reason I took up photography a couple of years ago. When I have good days I can go out and take pictures and on bad days I can stay in bed with my laptop and play with my images (in theory anyway

) So I can hardly complain about the limitations when it's the reason I started.
And I'm not complaining
I work around things as best I can. I too HATE auto and very rarely use it. My 17-55 and 70-200 have IS which helps a bit. My 12-24 doesn't need it really but the one I'm having the biggest problem with is the Sigma 105 macro. I'm trying to teach myself macro but it's so, so difficult keeping the camera still. I've got a proper neck strap (TP of course

) which I find helps and I brace my arms as much as I can and won't fanny about with the tripod outside as it takes too long. I've not thought about a monopod before. Are they useful do you think for the kinds of problems I've described?
I made it over to the TP Convention last year and that was great. I've currently got an exhibition running at the town museum (this is my second exhibition) and have been asked to do another one in Lorca,so, despite everything, my innate stubborness keeps me going
You can check out more details if you want
here and
here.
Jill
ps MM, I'm in Newcastle for a few days towards the end of May (I'm from the NE originally), so if you'd like to meet up that would be good.