I was under the impression you had to dump it each time as I do with the film developer
The general advice seems to be that for the "best" performance using tray development that paper developer should only be used for one session. I re-bottle mine and have failed to see any difference in new and 1 week old paper developer. Even 2 week old seems fine, but I don't keep longer than that. There again I do only print a few prints each session so my developer doesn't get fully depleted. I use Ilford multigrade ad also warmtone.

I understand the nova tanks with the floating lids do allow extended chemical working life but have never used one.

There is other equipment I need to get too, for example, print drying racks
perhaps nice to have, but RC paper dries fine clipped to a line and FB dries super-flat if you tape to a piece of glass using gummed tape (I use a piece of toughened that was the front of an old TV).