I never had a Persian, but I did have a huge Himalayan cat for several years, and he had a big huge fluffy coat of fur...I wound up brushing him, a couple of times a day...I did it that often, because he just loved it and it was soothing to me...
I did notice tho, that when we would be away for a couple of days, and had to leave him alone in the house, with his food and water supply provided, he needed immediate attention in the grooming area, as soon as we returned...just a few days of non-grooming, seemed to result in knots, and I hated trying to get those knots out...
So I just continued to groom him every day, with his special brush....when he died, he was buried with his front paws wrapped around that brush, as he loved it so much...as soon as he would see it, he would jump onto his kitty condo, next to my chair, and wait to be groomed...
These cats had a Himalayan mother and my last kitty had a Himalayan father. They are the same cat breed but I am shocked at how different physically these two are from my last one.