For years we have gradually been adding weeks to our "Timeshare Portfolio (stable?)" Each had to meet the following criteria:
Be a week that we would be happy to use ourselves every year but would also have excellent rental and trade power.
Be dual-affiliated with RCI and I.I.
Preferably be part of a timeshare group like VRI which has internal exchange privileges to many desirable resorts at a lower price than RCI charges. I know Points can accomplish the same results but the conservative side of my personality prefers to own a fixed deeded week that will be ours to use no matter what.
Using the above game plan, we now own 5 February weeks, back-to-back, at a Ft. Lauderdale resort that we really love. They are 2 bedroom lock-off units which come in very handy, since we bring our 92 year old mother with us. She keeps rather "strange" hours and has been known to get up at 3:00 a.m. to cook up a hearty dinner (or breakfast)

Our r/t airline tickets from NYC to Ft. Lauderdale cost $170. r/t. this coming year, on an airline that does not charge for the first checked bag (yet!). We were able to get this good price by booking early--something best done when one knows the exact dates they need.
We had planned for years to buy a second (winter) home or condo in Florida when we retired. These timeshare weeks have saved us the expense and year round worry of long-distance ownership. Our 5 weeks of maintenance fees covers all the insurance, upkeep, refurbishment, repairs, cleaning service, on-site pool, exercise room, etc...
Each week rents well, and trades as 2 weeks for one with RCI, II, and VRI. Rental of the lock-off unit would cover 80-100% of the m/f for the entire 2 bedroom unit.
In the summer we own 2 weeks at the New Jersey shore (beautiful beach, average older resort, recently extensively renovated). This is an easy drive-to trip for us--less than 3 hours. Once there it is a 10 minute drive to the Atlantic City casinos where we enjoy the superb restaurants and entertainment (and slot machines

).
In August we own 3 weeks back to back in a duplex timeshare unit in the heart of Cape Cod. It's a 3-4 hour drive, depending upon traffic.
We own a couple of "dog" weeks purchased for pennies back in the mid-90's when we didn't know enough about timesharing. They were great traders when Crystal DeHawn owned RCI and made sure that deposited weeks went only to timeshare owners. I still manage to get good exchages, generally during the last minute window e.g. the Manhattan Club--3 times! (But the recently enacted 1 in 4 rule has closed that wonderful door).
Most of what we own costs around $100. per night in maintenance fees and provides a comfortable vacation for up to 8 family members and/or friends. Most can be reached by car or low cost airfare. And most can be used to obtain great trades if and when we want to go elswhere.
Our trades have included weeks in London, Denmark, Italy, 4 Hawaiian islands, Cancun, Mazatlan, Puerto and Nueva Vallarta, Freeport and Nassau Bahamas, St. Maarten, Aruba, and all over the U.S.--Sedona, Phoenix, San Francisco, San Diego, Santa Fe, Willaimsburg, Alexandia, the Catskills, Vermont, Pennsylvania, etc...
Our game plan allows us to cut expenses to the bone, if necessary, or to plan more expensive trips, using exchanges.
I believe that almost every healthy person should consider a vacation at least once a year to be more of a necessity than an extravagence. It can be a great family bonding experience, a chance to relax and rejuvenate and to reflect upon goals and lifestyle changes needed, etc... Many studies have indicated that vacations can have a positive effect upon a person's mental and physical health.