Pee behavior solved!
My 6 year old, 19 lb Maine Coon stopped using the litter box after I returned to her from my vacation. I have been using pine pellets for years because clay type and crystal products stick to my hardwood floors making cleanup a chore and clay cat litter has negative effects on landfills. It doesn't decompose, potentially contaminating groundwater. Additionally, the mining process for clay can harm the environment (google it). One con is the high price. I have 5 cats, need I say more?