Geoff, I have I am still using after twenty years , they are great.
Now a couple of useful hints:

Only use the solid end for water pans, use the end with the bung for nesting bowls for your breeders.

Pick up some old garden hose that someone tossed out. Split it lengthwise, and "liquid nails" it to the edge of the pan. It will save possible foot issues when they stand on the edge.

Now then the center of the barrel.... Cut them in 10-12" widths. Take them and bury them anywhere you have root producing plants... Place them around the plant. It will stop them from becoming invasive and over taking you garden. Works great on any herb/flower/ivy etc that propagates through root travel.