Hopefully you will be flying a lot after you get your PPL and won't have to worry about these minimums.
Per the FAA regulations you will need to maintain currency to carry passengers which involves at least 1 flight every 90 days with 3 takeoffs and landings. Our internal requirements are much higher and depend on the make/model of airplanes you want to fly. But typically you will need to fly at least 1 time every 60 days for most training airplanes and every 30 days for more complex airplanes. Additionally every 2 years you will need to complete a Biannual Flight Review (BFR) with an authorized instructor. You will also need to renew your medical every 2-5 years depending on class and age. Hopefully you will be flying a lot after you get your PPL and won't have to worry about these minimums. We find that pilots that fly weekly or monthly tend to stay sharp after their training which is good for safety!