I have used lava rock in the bottoms of some really deep pots to save on soil.
I do block holes in pots either with landscape cloth or aluminum screen.
I reuse poiing soil all the time. I either mix old in with new I'm making or add it to compost pulled. The compost ends up in putting mixes anyway.
I use reclaimed bricks under pots as pot feet. This make a really stable base as well as provides lots of refugia for lizards and other critters. Those with more formal looks might not want to see brick however.
