
High-traffic areas (here close to the front door) haven't held up well.

The south steps and all other areas that get more sun seem more susceptible to paint peeling, which isn't too surprising given that we're in a high desert.
We scrubbed the porch with wire brushes trying to knock off loose paint, as the issue here may be that we've previously applied paint over flaky paint, so it's not sticking well. Lisa concluded that we needed better tools, so a trip to Lowe's was in order.

We bought the tools you see here (except the Shop-Vac, which we already had), which includes, from back to front and left to right:
Metabo HPT model SB 8V2 belt sander (still in box).
Course and medium sanding belts (grades 40 and 80).
Adapter to connect the sander's exhaust to the Shop-Vac.
Our existing Shop-Vac.

We ended up not using the vacuum/adapter, but relied upon the bag attached to the belt sander to collect sanding dust. I dumped the sawdust/paint combination a couple of times.

Using the Shop-Vac would have meant needing an additional electrical cord. Lisa decided she could do without it, but it's comforting to have the adapter should we later decide otherwise.
I had cleared everything off the front porch earlier today, so late this afternoon, Lisa tackled sanding off old paint.

With her respirator and eye and ear protection, Lisa started grinding away old paint. She discovered right away that the coarse (grade 40) sandpaper was too coarse and was taking away too much wood, so I fetched the medium (grade 80) belts we also bought. The belts are from Gator Finishing Products, are US-made, and have the added advantage of not being directional. Some sanding belts only work one direction, but with this brand you don't have to worry about having put the belt on the correct direction.

Lisa sanded, while I generally stood back a few meters with a broom or brush to sweep stuff away when she stopped. I wore one of my cloth masks and didn't want to get too up close and personal with the find dust generated by this work.
The belt sander was clearly the right tool for this job. Sanding and chipping at this porch by hand wasn't getting us anywhere, whereas Lisa covered the worst parts of the porch in only a couple of hours.

When I was sweeping, Lisa peeled off larger chunks of paint that came off in pieces.

She went through the first grade 80 belt (left) and replaced it with a fresh one.
As daylight faded, Lisa and I cleaned up. She used the leaf blower to blow away as much debris as possible (and the blow the sander clean), and we inspected the results.

This may not look much different than the "before" photos, but it really is much less 'chalky' than it was before Lisa started.

The north steps get less sun and didn't need to have as much paint sanded off as was necessary on the south steps.

The front porch rail needs a lot of work. Lisa also removed and replaced a number of wood screws that were no longer holding down boards, drilling replacement screws along the crossbeams to re-secure the porch boards so they won't wiggle the way they were doing.
The new sander and supplies cost a bit over $200, but it was worth it, as it made a week-long job take only one afternoon. Lisa may go back and do some more spots before she starts painting, but this was the worst of it. Just as the expensive impact drill made drilling anchor holes in concrete and masonry simple, this belt sander works just fine for sanding larger areas.
Lisa tells me that the next step will be to apply sanding sealer, which should act as a primer coat. Earlier this year we bought four gallons of Sherwin-Williams Fireweed Red to use for this repainting job. We hope this lasts longer than the last job, as we'd rather not have to repaint every year, but we also want to project and preserver the front porch. Indeed, the last few weeks have been one of the two times each year when the weather is nice enough that we can spend time in the last afternoon/early evening sitting outside and watching the birds and bunnies and generally enjoying our house without being broiled or frozen.