While you shouldn't expect your Tru-Tone bulbs to fail prematurely, if you do have a bulb die, the rest of your lights will remain lit.
All modern threaded base bulbs (including our C7, C9, and S14 bulbs) are powered with the light strings wired in parallel, not in series, so each will receive 120 Volts AC from the light string regardless of how many other lights may or may not be on the string, or if one experiences a failure.
Tru-Tone covers premature failures, so be sure to reach out to us if you find yourself in this situation!
Please note that our mini lites, due to their different voltage requirements, are wired differently and thus require a bulb in each socket so that each mini lite receives the proper voltage from the power supply.