It may seem redundant and some will scoff at the idea but there is a simple way to do a sanity check on tests. I find many people do have trouble with getting the correct results with liquids when they first start testing. There are numerous ways to skew the results. So, even though the test strips are not as accurate, they can do very well as a test to cross check your liquid tests when you get weird readings.
They may not be top grade but there are few ways to screw up the readings if you can time 30 and 60 seconds! I find the cheap Jungle brand from Wal-mart gives me a quick simple check for trends on the things I want to see stay the same like PH/GH/KH.