For quite a few years now I have been using two recycled computer desktops for a work and assembly bench(s). Both had been discarded at work. One was a printer desk with the tractor feed paper slot cut in the top, the other a regular desk.
The printer table was used as a low base workbench with the addition of wheels. The printer slot made an ideal place to set clamps for gluing. I also added a shelf with dividers that holds all my small workbench odds and ends like tape measures, sanding blocks, pencils and things like that. The bottom and back shelf holds all my heavy goods like boxes of air gun nails. It makes for a very stable unit.
The other desk I stripped the top right off and sent the base to the scrap yard. I added hardwood bracing and wide feet to it, making sure it stayed flat and true. It now sits on top of the base unit at just the right height for assembling small projects.
If there is a tall project to assemble I simply take the upper bench off and stand it in a corner or set it on sawhorses if I need the extra room. The sawhorses were made so when the top was laid on them it is the same height as the base bench, giving me a lot of top to work on.
They have taken a beating, drilled into, jig saw cuts, dropped on its corners, hammer dents, file scrapes and what not and the only thing that really harms the tops is moisture.
They must be wiped off immediately if they get any kind of moisture, oil, or cleaning fluid on them. The particle board swells up in no time. The thin arborite top is a lot tougher than you might think, but the moisture will get into hairline cracks and drill holes and such.
I expect they will last a while yet, I’ve had them for about twelve or fifteen years now and they cost me about twenty dollars in material to outfit them.