I'm back, having read all your excellent suggestions and having had a wee think about the situation.
I said earlier that I had lost the will to live after hand keying a couple of door frames.
Meantime, while thinking about it (I don't like to waste time

) I have hand sanded some more.
If I get another few days with good weather to be able to open all windows without freezing to death, I will soon have finished the job!
On clearing out a cupboard I have found guess what? A sanding block and lots of sanding paper!
Obviously I am meant to do this by hand, so I will go down that route ... only 8 door frames left to do

I'm also getting a loan of a small sander to try, I'll see how I get on, maybe for a quick skirting boards sanding.
I'm late 60's and just finished painting all house windows and exterior doors, mist of which also needed some repair and filling and a key and I did it all by hand
Kudos to you, I changed all mine to double glazed UPVC - I'd rather be gardening or cycling or baking or reading

I do work full time though, sometimes 6 days a week, must prioritize stuff that makes me happy ... sanding isn't it!
I have a rather excessive number of sanders, even though it's just for home use,
Yes, yes, I have a rather excessive number of baking tins and gardening tools

vibration is a huge factor over a period of time,
Thank you: I did think of this, already got arthritis in my hands, wouldn't want to aggravate it.
The upside is that if you do use proper dust extraction you won't need to worry about dust getting everywhere although using a mask is still a good idea.
Considering I'll soon have a small army of workmen in the flat, I probably should not worry about the dust I will produce with my sanding
Might be worth considering chemical and/or hot air paint stripping options to minimise the amount of sanding.
Not worth it for this kind of cheap wood: I did this years ago on lovely detailed doors, but my doors and frames are cheap. I remember it being quite pricey for the chemical and time consuming to get all the paint out. No need to do this in my present flat.
Actually this would probably be my choice for lots of door frames - with a scraper you can get into all the detail areas and it will properly remove all of the paint.
The wood I'm keying for painting over is quite plain, no details.
One "fristration" I have with hand sanding is that I lose the ability to unlick my computer devices using my fingerprint
Oh, I could never do that anyway.
My fingertips are eaten up by the cleaning chemical I use at work, goes through the supplied gloves.
I buy my own marigolds now!
I wore a pair of soft thinis rubber glover (thicker than nitrile but soft and flexible).
Yes!
I did get them for gardening, but I used them for sanding, they are great.
are they actually that bad they need sanding Pat? quick run over any obviously rough bits by hand, wipe down with a soapy cloth and paint away?
BTW you have too many doors, you need to embrace open plan living
You are correct for some of the paint. However, in some of the frames, about 4, they used a layer of that cheap gloss that turns yellow, that one I really must sand down.
I know I have too many doors for a 2 bedroom flat!
There is a corridor with 3 cupboards, plus each of the bedrooms has an extra door to access a common built in wardrobe/storage area.
Then the doors of the 2 rooms, the living room, the bathroom and the kitchen!
I have already changed the back door to UPVC, no sanding or painting required.
I'm not counting the front door, because when I get a new one the frame will also be changed.
I did wear a mask and googles through when I sanded the walls down as that was unbelievable.
No walls will be sanded, ever!
Have you considered spray can primer instead?
No, because I don't know what it is
