You are supposed to get it checked every 6 months... regardless. Statins are nasty drugs... you want to make sure you keep up on your blood tests when taking them. You want to find out sooner, rather than later, if statins are causing you an issue. There is no way I would wait a year between blood tests when taking statins. They can cause a Rhabdomyolysis, a very rare side effect.
Rhabdomyolysis is a fatal side effect of cholesterol lowering statin drugs that was responsible for the eventual recall of the Baychol in August 2001. Defined as a disorder involving injury to the kidney caused by toxic effects of the contents of muscle cells, rhabdomyolysis can become fatal. Baycol was the first statin directly linked to death because of rhabdomyolysis.
When the muscle is damaged from rhabdomyolysis, it releases pigments from the muscle and blood into the bloodstream. The kidney then filters the pigments out of the blood and it accumulates in the kidney and blocks up the filtering portion of the kidney, causing kidney failure.