How do I remove & replace the plaster going up my stairs?

Is that plaster or wallboard?

You can buy thin drywall and cover it. It is gthe least messy option.

Best and easiest solution is to put drywall over it. Too much to repair. Can't be repaired. Would need to be totally removed down to the lathe and replastered. That is not a DIY job.

I'd call a plaster co to price resurfacing or repair before making the decision to replace. Removing plaster is extremely messy. You have to remove all baseboards and trim carefully to put back up, especially stair trim.

Then install new drywall. May have to fur out some of the studs, they were not always the same size like they are today. Plus there will be lathe work behind the plaster to remove. Very big job.

Simply go to the paint store and buy a bag of plaster of Paris mix .it comes in a bag , just add water. Just play with it and by the time you get pretty good at patching plaster walls , you're done and it's time for something. A little morw fun ,........like painting . unless there are huge chunks that have fallen out and you can see metal lathe in places , I would just patch it . the walls are much better built to hold the plasters weight and the metal is a CHORE to remove. Ive patched holes in some walls in a school that had holes the size of grown people and you never knew after a little paint .