Your Product Will Be Buggy

No matter how thoroughly you test your product, no matter how many quality control measures you put into place, any new or significantly-enhanced product you release will be buggy.

Some good quality control measures include:

1. Your product manager gathers realistic usage scenarios from prospective and existing customers.
2. Your testing team maintains a suite of regression tests, adds to them as tricky new scenarios come to light, and runs the tests on a regular basis.
3. Your developers maintain unit tests and run them on a regular basis.
4. Your developers review each other's designs and code.
5. You release beta versions of the product to customers.

Yet even with these measures in place, your product will almost certainly contain defects. Part of your release plan should be to put mechanisms in place to efficiently process defect reports, fix them promptly, and enable users to obtain the fixes as quickly and painlessly as possible.