Are only good for a couple of years . 5 at max. The reason why is that one of there jobs is to remove moisture from the system because moisture is a non condense-able and moisture plus R-134A equals Hydrochloric acid, which is not good. After so long the internal desiccant bag becomes over saturated and can no longer do its job.
The primary job of either two is the separation of vapor and liquid freon. The drier prevents vapor from passing into the liquid line and the accumulator prevents liquid freon from passing through the vapor line. I know it sounds a little confusing but try to think of it like this.
If any vapor leaves the condenser and makes its way to the evaporator then you loose that much cooling efficiency because vapor cannot collect heat and if any liquid is allowed to leave the evaporator that has not converted to a vapor then it will travel straight to the compressor and " Slug " or damage the compressor since liquid does not compress.