A good way for me to figure out if I've done a survey, or at least looked at it, is that the view a hit link becomes purple rather than blue after I've clicked on it. If a survey is reposted, this goes away. It's such a hassle when a survey you've done is reposted and they tell you not do take it again. A lot of the surveys are very similar to each other even if they aren't by the same requester, and it's often hard to remember if you've taken it or not. Some won't even let you see it until you've accepted it.
I was having the same problem, but the other day I downloaded a script that tells you if you have already done a certain hit or not and it's been working great. So much easier. I found the link to it in one of the forums on this site.
Or you can make an excel document and manually fill it in. Then when you aren't sure, search the document.
No, not exactly. The script is awesome. You can look by requester # to check (in case they change names!) as well as the HIT. Like if SprinkleButts posted a survey on cupcakes, it would search either for SprinkleButts # or "A brief survey about what you like on your cupcakes" =-) Then if SprinkleButts posted "Filled or unfilled, what's your cupcake of choice?" You know it's not the same survey.