We recommend replacing Flip paperboard liners when there are signs of wear and tear to keep bacteria and odor in check. The longevity of the liners depends on how much litter is used, how many cats use the litter box, and how ferociously they scratch. Daily scooping and sustaining the litter level at 2-3 inches (5-7.5 cm) will maximize the life of the liners.
I gave these 4 stars because they seem like they'd be great for most other cats!
Unfortunately one of mine pees up the side of the box. She's the reason we chose the flip box in the first place (which we love!!)
Unfortunately the plastic piece designed to hold these liners in place doesn't sit as flush to the sides as I had hoped, so when she pees up the side of the box it soaks into the liner immediately. Wish this could have worked for us, but we really need something that covers the full sides of the box.
I actually like the cardboard better than the tarp liner.
Trying out paperboard liners.
I just started using the paperboard liners. They seem solid so I think they might solve the problem I have with the reusable liners that leak urine into the plastic box. I would like to suggest that you make the paperboard liners using the same patttern as the reusable with corner perforations so the paperboard liners can be secured with the corner hooks. I had to tape the paperboard liners to the litter box since the sides flop down and I know my cats would paw the sides and make them collapse.