Camry :: 2014 - Replacing Of Rear Shoes - 4mm

I have no experience with drum brakes. I have no clue how long they are good for and what to look for in terms of wear. I assumed last week that with 226K miles on the car that the shoes must be reaching the end of their life. I went on Ebay and bought the spring kits and new shoes.

The last time I inspected the shoes was when the car had 100K miles on it. They didn't look too bad. When I started to replace the shoes after just buying all of the parts they looked almost the same as they did when the car had 100K on it. The rear facing shoes are about 5mm thick and the forward facing shoes at the thinnest part near the middle are 3mm thick. The specs in the maintenance manual give 5mm normal and 1 mm minimum.

Since I already have all of the parts and can't return them should I replace the shoes anyway? The manual says if the shoes show uneven wear to replace them. The rear facing shoes have even wear from top to bottom while the forward facing shoes are thicker on the ends and are thinner in the middle. The only issue that I have with the rear brakes is with the parking brake. I have the parking brake cable adjusted all the way and it will barely hold the car in place while in neutral. The shoes that I purchased are made by Wagner and being brand new are not even all the way across. They are also only 4mm thick.