It's normal for one side to wear a bit more than the other, but if there is a pronounced difference on one side and not the other, one side is binding.

You have two things to check here -- the condition and performance of the piston seal and the condition of the pins and bushings on the floating caliper.

If you have a bad seal, one side will drag more than the other, leading to some steering pull after a stop and greater pad wear.

If the pins and bushings are worn, the floating side of the caliper will wear to a taper, the brakes will rattle, and you will have reduced braking and higher pedal effort. You can check this either by looking at the pad for taper front to rear, or by attempting to move the floating caliper sideways. If it moves in any direction other than straight in and out, you need new pins and bushings. They just screw in, new ones will have locktite on the bushing thread.

Replace the torn boots and relubricate the pins in any case, else they will rust and stick.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!