When opening your pool it is important to do a few checks beyond the standard equipment start up/maintenance. For example:
Ladder bumpers - If they are worn, the ladder can cut into the liner.
Zinc balls for salt water pools- The zinc ball is a sacrificial anode which keeps the salt from corroding metal ladders handrails screws etc.
Pool Filter Sand changes- should be done every three years this will help with water clarity and prevent strain on your pump and equipment. Also, over time the sand gets hard like cement and cannot filter.
Make sure there are no leaks in your pool or pool equipment, and that you are not losing water. A leak can significantly raise the usage of pool chemicals and their cost, and possibly burn out pumps and ruin a liner.
Never let your sanitizer get low that puts you at risk for costly algae blooms, and bacteria.
Never let your PH get low- low ph is acidic, and will ruin your liner and corrode your heater.