The delivery address is missing a unit number; how can drivers avoid wasted trips before heading out?

When doing parcel delivery, the most annoying thing is when the address in the manifest looks complete, but upon arrival, you realize it's missing an apartment number or suite. I used to think you just had to call once you were at the door, but I later realized that many wasted trips can actually be prevented before leaving the station. Once, on a commercial route, I had three packages that only…