You walk in with armloads of groceries, and the hallway lights turn on by themselves. At bedtime, one tap shuts down the entire downstairs so you never walk back to check a switch. Swapping out every bulb in an average home takes an afternoon, but buying individual bulbs at the hardware store adds up fast. Compare bundle quotes from two or three major retailers during major holiday sales events to get the best pricing per socket.
Doing the whole house at once usually runs about $450. If you do not want that cash leaving your checking account on a single Tuesday, you can spread the cost out cleanly without paying interest.
A 0% intro rate is a timer, not free cash. Once the 15 months end, the standard variable APR hits whatever balance is left over. Set up an automatic payment of $30.00 each month from day one so the balance is gone before the promotional window closes.