Is once every 2 weeks ok for bedding change?

Hi all,

I currently use pure comfort white bedding for my 3 female rats. Currently my cleaning regimen goes as follows:

• Every 2-3 days fleece and soft items are changed

• Every 2 days litter box is changed/cleaned

• Every week I change the bedding on Sunday

• Plastic is wiped down every 3 days with white vinegar/water mix

I've noticed they get kind of annoyed each week when I replace the bedding and then they want to scent mark even more. This this kind of absorbent bedding, can I move to doing it every 2 weeks OR perhaps only take 50-75% of it out every week? I dont know if im stressing them out with the frequent changes but I also dont want them to get sick from any ammonia build up!