Usually I hear about exhaust rusting through on vehicles that don't get driven long enough at a time to dry out the exhaust, short runs after a start up will kill exhaust pretty quickly. A vehicle has to run at least a 1/2 hour after it reaches operating temp to dry out the exhaust. When a motor first starts, the combustion process creates an acid/water mixture that will dry up as the exhaust gets hot, the drying process begins at the motor and works its way towards the back. that acid/water mixture rots the exhaust from the inside outward. The muffler and tail pipe are usually the last things to dry out. That is why welding exhaust with holes in it isn't often successful.

Somehow I just can't see that being a problem for you. Either you have been doing a lot of short runs lately, or they must be really making mufflers cheap these days. Gene