is it strictly necessary to sand paintwork before repainting?

[MadamNoo]

I have acres of skirting board and banisters to do and can't imagine how long it would take. can I just sugar soap it? going white over white

why not sand it? Less mess and effort than sugar soap!

I think a light sanding is best. You need to make a key for the new paint to stick to, otherwise it might peel off.

Not strictly necessary no. But it usually peels off and looks a total mess. Then you have to really sand it all back learned the hard way

Got any short people who might like to play with a power sander?

Yes you have to sand. Previous people in our house didn't and its a peely mess, takes forever to put right.

It won't take long, you don't want to sand it back as such, just scratch the surface so paint has something to cling to.

I didn't sand in our house, didn't know you had to... And nothing has peeled, it looks fine even 10 years later. Well, grimy, but the paint itself is fine.

We usually give it a quick rubdown, it doesn't take much just to key the surface.

My Dad never bothers though and I have to say their house looks great.

I always would. If you're not using the same finish (eg: eggshell on old gloss), then absolutely yes.

not here

I didn't bother ... almost a year on it looks fine. Just rib it lightly with sandpaper it doesn't have to be a lot.

Annie Sloane is your friend.