A reservation where products are sent/sold, but not returned. Typically the sale of equipment or consumables. Ex: You sell a fog machine to a night club.
A reservation where any item is expected to be returned from an event.
There are some instances in which you’ll be selling some items while renting others. Ex: You rent out a confetti cannon, so you’ll expect the cannon itself back, but you won’t be receiving any confetti. In that scenario, the confetti would be a Sale while the cannon would qualify as a Rental.
When a reservation requires an operator/technician along with equipment or products. Ex: Not only are you providing lights at a venue, but you are sending your own operator to control the panel.