The beneficial bacteria live in both the filter media and in the gravel/substrate. On all of my tanks I use a sponge (filter type) over the intake of my filter. It keeps small fish, snails, and shrimp from getting sucked up in the intake of the filter. It also is another place that the beneficial bacteria build up.
The key is having enough bacteria that they can keep up with eating the ammonia the fish produce. Basically, I change my filter when I need to and don't worry about it. That is because the sponge filter on the intake has bacteria and so does my substrate. I never clean everything all at once so as not to disturb the balance. When it needs it, I will clean the sponge on the intake but not at the same water change that I clean my filter media (when it needs it) or when I do a huge substrate cleaning.
Sometimes there is an additional sponge media within the filter canister. If that's the case, it rarely, if ever gets changed, and then, not when the others are cleaned.
So the answer to your question is no. It is not necessary to pretreat your filter cartridge once your tank has cycled (built up the beneficial bacteria that eat the ammonia your fish and other critters give off.) Just rinse it well with some tank water (into your sink) when you deem it necessary to change. And unless the old one is breaking down, you can rinse that one out the same way and use it longer.
The best way to know if what you're doing is working is to get an API test kit (not the strips) and find out what your tank's parameters are. By testing and getting reading before and the day after you do a water change, you'll then get the feel for how often and how much attention your fish need. This will change as you add fish, live plants, or anything else.