I've kept the rubber plunger out of the tube when in storage. When kept inside the tube it compresses the rubber and retains the shape memory which causes it to fail. Haven't ever replaced mine and it is eight years old. Still works perfectly.
My original one i had to do this but the one i have now, if you fully depress the plunger with no coffee in it it comes out the bottom just enough to not squeeze the sides.
Just push the piston all the way in, and the rubber clicks when it comes out the other end of the cylinder. This way you can store it in a compact package.
Interesting. I’m using the AP Go, so maybe the normal one doesn’t extend all the way through.
Edit: just checked how my normal AP works. It’s basically the same as the AP Go, but I guess this is a fairly new model, so there may have been some changes.
It seems that the older models had a problem that was fixed. So, the tip needs to be tweakws a bit.
If you have an older model, store the pieces separately in order to prevent the rubber from being under constant compression. If you have a newer model, push the piston all the way in until the end of the piston pops out the other end. Oh, and that is only possible if the cap isn’t screwed on. That piece needs to be stored separately anyway.
Mine died after 9 years or so. Did that thing where the rubber breaks down and gets super sticky and oily. Never had an issue with it losing its shape - you just have to make sure you store it fully pressed in so the lip pops out the far side of the tube
I’ve found you can extend the life of the plunger by placing the plunger rubber-side down on a table or counter top, tilting it slightly onto the edge of the rubber and then rotating it. This essentially presses the rubber and extends it outwards and seems to help achieve the seal you expect. I’ve been doing it for a while now and it’s worked well for me.
I’m sure it won’t last forever but it’s something worth trying to get a bit more life out of it.
I didn't do that and it lasted a decade. Just don't store it compressed in the tube or wash it every day (just rinse or rinse and wipe. Dish soap dries out rubber.
Mine lasted literally 10 years before it started to go a bit. I blame half that on my spouse using it for non coffee things and scraping up the inside of the cylinder pretty badly.