If you turn off your lights and the bulbs are still glowing a little bit, or one of the bulbs in your circuit doesn't want to shut all the way off, you have what we call a "ghost current" in your circuit. This happens when there is excess energy leaking into the bulbs even when the switch is in the off position. This could be happening for a variety of reasons.
Ghost currents can occur if the bulbs in the circuit are operating on lower power than what is flowing in the circuit, or if the circuitry is too old to properly regulate the current. In essence, these problems can be solved by installing a LED dimmer in the circuit, or updating the wiring in your home.
LED dimmer switches do a better job of properly regulating the current that flows into the circuit. This is key for getting rid of ghost currents as well as making sure that your LED bulbs perform at their best!
To prove that this is the issue, try putting one of the old bulbs back into the circuit. In most cases, you will find that all of the bulbs in the circuit will now turn all the way off! This is because that older, higher wattage bulb is soaking up the excess current in the circuit.