You check your phone from work and see the front porch clear as day. A smart security camera system gives you that peace of mind day to day, and setting one up usually takes just an afternoon of drilling and syncing apps. Black Friday and Cyber Monday are the best times to buy, when manufacturers slash prices on gear and bundles.
Before you pull the trigger, get at least two installation quotes if you aren't doing it yourself. Prices vary wildly between local techs and big box services, and comparing bids keeps you from overpaying for the labor.
That 0% window is a hard deadline, not free money. If you still have a balance left when those 18 months are up, the card will hit you with deferred interest on the original amount, so make sure your monthly payments cover the whole bill.