That's good advice. We put a dish pan underneath the filter. The usually catches all the spills. Also a container of water on hand is nice to clean/rinse the filter holder if you have that type of cartridge filter. Remember no water once you remove the filter housing.
2013 New Horizons 37' Majestic, 2013 Ford F-450 Lariat
Full-time RV April 2013, Retired January 2014