Well the developer may develop 'chunkies' that may clog any developer sprayer or pump orifice mechanisms. I drain my Fujimoto CP31 (no filters either) after each use if I am not going to use it the next day, and rinse it out. I filter the dev though a coffee filter if it is getting 'mungy', and sprayer holes need unplugging.
I replenish about every 8 or so sheets of 8x10 at a rate of 20mL/sheet. I pour straight into the tanks with the cover off when there are no paper bits in the transport. the overflow goes to jugs off each tank.