p5gal5 - 2:27 pm on Aug 31, 2010 (gmt 0)
Well, on priority mail w/confirmation "click-n-ship" on www.usps.com will not allow invalid addresses, but both Endicia/Dazzle (the name of their software) and Stamps.com will allow you to override that. Since we swapped from click-n-ship to endicia, we have not had a problem with returns from these previously "invalid" addresses. Like dpd1, I also found that the invalids were usually people living in the country submitting their RR street address, not their PO box (despite selecting US Mail as the shipping option). Also, the endicia/dazzle software gives you suggestions on what might be the issue on the address - flying blind with click-n-ship.
We were always using 1-up 8.5x11 labels, dymo or postal meter tape for our labels, but now that we use endicia, we use 4x6 for everything (including first-class). IMO, this is the biggest time and cost savings. Waiting in line at the PO was too time-consuming, dymo labels and postal ribbon/tape are expensive and usually required multiple labels, so we purchased a direct thermal Zebra printer. Looks as professional as any amazon shipment, can print mail-to, postage and return address in one fell swoop. We buy the labels in boxes of fan-fold (get much more than the rolls) and costs less than $0.02 per label. Since they are direct thermal, no additional ribbon/ink/materials are needed.