Salespeople may well overstate things, if anyone is surprised by this when you are buying anything substantial ( cars, appliances, houses, etc.), well you need more help than anyone can give you.
That said, we have been Marriott owners for 15 years this year. Never had a problem trading, have traded "up" plenty of times, etc. If the original poster has an Orlando Marriott week, and they want to trade within the Marriott system of around 50 resorts. It is virtually impossible not to be able to find someplace nice to go as opposed to "never" using it.
The advice given to explore TUG - is spot on. Lots of knowledgable people to help TS owners learn how to maximize the investment they have made.
Some basics, I have learned from that sight are as follows:
1) buy where you like to visit - so if you can't get at trade at a time you want, visit your home resort.
2) Yes there are seasons - don't expect miracles. Trading to Hawaii at peak times is a difficult trade for anyone. If you have a low demand week at a low demand resort - then trading is likely to be more challenging. What I mean by that is, if you own "mud season" at a ski area - that time frame is not worth much, so lower your expectations accordingly, and better yet ask yourself why you would even buy that week.. FYI - An Orlando Marriott is certainly not the highest trader, but all the weeks are pretty darn good.
For Example: We own what I consider to be decent weeks (good weeks not the highest demand areas ) in Orlando and Palm Desert. We have traded most years, almost exclusively during school holiday periods, (spring break, winter break, etc.) We have always gotten a good trade, Cayman Islands, St. Thomas, Hilton Head, Williamsburg, Florida Coast, Disney weeks in Ca. and Florida, more Ski trips to Vail, Breck, and Park City than I can count, and even a trip to Hawaii. Trust me - we've gotten our money's worth.
3)People who plan ahead get the best results. Me, I never worked that hard at it, and couldn't plan more than 3 to 6 months advance and we always had good luck. But I always was willing to travel to a different location if my first choice wasn't available. I've never once been stuck.
4) refer to rule number 1 - trading is an option and since you have to complete a trade it should not be taken as a "given" that all your wishes are going to come true. Be flexible, and find a way to make good use of your weeks. If its not working out - visit your home resort within your season - what's so bad about that.
5) Timesharing isn't for everyone. There is a long term financial responsibility you are taking on in the form of maintenance fees. Remember its every year you need to use it or every other year if that is what you bought. Simply put, it is a commitment in both time and money. Don't buy if you don't fully understand that.
6) A timeshare is not a good financial investment - assume on a cash basis its worth nothing, because many of them are. Look as it as an investment in family or personal time and you'll get a good return. If you buy a major timeshare from Marriott, Hilton, etc. as a resale you'll likely be able to get a very good price and you can use it for a number of years and likely sell at a price close to what you paid for it. I own Marriott weeks from the developer - we'll never get close to what we paid, ever. I am not mad at Marriott, just sorry I didn't research it more before buying. Marriott has fulfilled what they sold me, I just paid a lot for it. After I heard about TUG, I bought a resale Marriott week and I likely could get what I paid or certainly close since I follow what they sell for. I'm not selling, but its good to know what my weeks are worth in the real world.
7) Don't listen to salespeople - do your own research, educate yourself and make informed decisions about ALL large purchases you make.
I hope the original poster can figure out how to use their timeshare and begin to enjoy it.