I have been using the Legacy Pro Eco Pro developer, with I think excellent results. I have used many developers over the years.
The normal mix is 1+9. I decided to try this as a replenishing developer. When I am done with a printing session, I return the working strength developer to the storage bottle. I then top off the bottle to replace what has evaporated or been absorbed during printing, at 1+5. This was not in the instructions, but I just decided to give it a try.
I have been working one quart this way for almost four months, so the economy has been very good. A couple of times I have used a coffee filter to keep the developer clean.