Yes, these really work...but keep a few things in mind [SEP] After very minimal and barely noticeable success with whitening toothpastes and gels, I finally decided to give Crest Premium Whitestrips a try.  Previously, I had found the cost to be prohibitive, but the fact that $5 or $7 coupons are offered in our Sunday paper with some regularity made the price a bit easier to swallow.<br /><br />Just like the commercials say, I definitely did begin to see some improvement after about three days.  I would describe the effect as more of a lightening than a whitening per se:  the darker yellow spots on my teeth began to fade and to become less apparent.  Now, after using the product as prescribed for a week, the color of my teeth is clearly improved; I wouldn't say that my teeth are bright white, but they are definitely more of an ivory or a paler yellow color.  According to the package insert, you can immediately begin a second course of treatment for even better whitening effects, but I haven't yet decided if I want to lay out another $30 in order to do this.  Also, I should mention that the effect is not so dramatic thta anyone has noticed (UNLIKE in the commercials!).<br /><br />Now for the caveats.  First of all, I found these strips to be a bit difficult to use.  It can be hard to remove the strips from the protective backing without them becoming mangled, and it is very easy to get the gel on your fingertips (which causes a temporary whitening effect).  Also, the strips are not ideally shaped for your mouth, and I found that they covered my front eight teeth only.  Finally, while the top strip adhered fairly well, I found that the bottom strip was more tricky and tended to slide around, especially if I moved my mouth at all.  The only solution I found to this was to wear the strips while commuting to work, which luckily gave me a 30-minute period when I did not need to talk.  Otherwise, it can be difficult to find a good time to wear the strips, as the insert information advises against wearing them immediately after you brush your teeth, while sleeping, and while you are eating/drinking.<br /><br />Unlike other reviewers, I did not have a problem with the taste of the strips:  I could not detect anything while wearing them, and after taking them off, I thought that the gooey paste left behind was virtually tasteless.  I did experience some sensitivity in a lower tooth which I had capped over 20 years ago.  Although this sensation went away in time, it was uncomforable enough to make me cut the lower strip to fit around this particular tooth.<br /><br />In summary, I did see clear--although not miraculous--results from this product and I would be willing to try the strips again, especially if the price were to come down a bit.  Ultimately, I would rate Crest Whitestrips three and a half stars, as there is definitely room for improvement.