Rent to get a feel for different resorts, developers, activities, etc. Spend hours reading these boards. And stay away from the timeshare sales weasals.
T/S are easy to buy and hard to sell. Buy resale. And learn as much as you can before you buy a timeshare.
My sister and her husband are coming on a 6 day trip with me next month - I have reservations at 3 different resorts for those 6 nights. She is reading resort reviews online. She has visited 3 other resorts in the 18 months. She is, IMHO, still not ready to buy a resale timeshare yet or after this trip. Reasons include her blended family has two sets of weekend kids and her job has her traveling worldwide every 5-6 weeks. Good T/S vacations require planning 13-24 months in advance. She is still 15+ years from retirement.
But that is JMHO...