Do I need to worry about the shelf-life of my resin if I’m not printing very often?

Almost all print resins are supplied in sealed UV-protective bottles, so if it’s unopened, unless the resin specifically states a use-by date you won’t need to worry about shelf-life. Once opened, some resins may start reacting to oxygen exposure which can affect the material properties of the resin. Most resins, however, should be fine to continue printing with for up to 3 months after being opened.