I live in a condo. The buildings in my development all have wood siding and
the association has always used a "solid color stain" which, to me, looks
the same as paint. Over time, older stain peels off the way paint peels
off.

They are in the process of re-staining a few of the buildings. It appears
(without my watching their every move) that they first using a pressure
washer to remove any peeling stain and then as much as week later, the are
applying (spraying) a brand new coat of stain over the siding which still
contains older stain (since...my understanding is that the pressure washing
does not remove all the old stain...only what was on the verge of peeling)
They are using sprayers to apply the new coat of stain.

Is the above the correct procedure for re-staining, or are they supposed to
strip off ALL of the old stain before applying new stain?

The reason I'm asking is there have been problems with peeling stain on a
couple of RECENTLY re-stained buildings.

Thanks.

JY