When your clients are in the process of moving into their new home, there are plenty of details they need to keep track of. It can help remind them of a few things, especially one as simple as changing their address with the USPS.
Changing an address is a relatively simple process and can be completed online. USPS will only charge up to $1.06 or so for the address service change, depending on if you fill out the forms online or in person.
Some companies seem to offer address change services for up to $40 or more and claim to make a simple process simpler. However appealing these services may look, you must change your address with USPS directly not with a second-party system. Working directly with USPS is the only way to ensure the changes to your address are made.