Most commercial strings and cables creep a lot. This causes your nocking point to move and unless you frequently re-tune your bow, it is likely to be shooting poorly. When a string and cable creeps, it also changes your draw length, draw weight, brace height, ATA length and sometimes your letoff percentage.

I recommend changing a regular commercial string at least once a year. If you don' t, you at least need to re-measure it and twist it to proper length and re-tune your bow.

Doing it yourself is not hard if you pay attention. I recommend removing only the string or cable, changing it and then doing the other. It' s less confusing if only one is off, at a time.