I'll offer a slightly different take on it. Only go if you are truly interested in purchasing the property. There's usually ample time to figure out if it meets your basic needs before you go. When you get there, instead of asking the sales rep why you SHOULD purchase it- ask them why you SHOULDN'T.

If you're not sure, or you're worried about being talked into it, then follow pinniped's advice.

There are probably countless thousands of timeshare owners around the globe who were only going to a sales pitch so that they could get those FREE Luau tickets.