You have to use the control solutions or else the meter won't work correctly. I'm pretty sure the instructions to the meter say to calibrate the meter every time you open a new container of strips and/or weekly (or if dropped).

My own experience has been great over the past two years. I've gone through about 250 strips and only 1 bad sample.

The control solutions have a shelf life, too.

It's always a good idea to make sure your equipment is calibrated and zeroed before you make any measurements. :)