One of the most important things to be aware of is that paint is formulated for either interior use or exterior use, and they have different properties: Interior paint is formulated for: Scrubbability and stain resistance; Good hiding ability; Splatter resistance; Easy touch-up. Exterior paint is formulated for: Color retention; Resistance to fading; Flexibility to withstand expansion and contraction due to weather; To provide a mildew resistant coating; Resistance to tannin bleed. Don't think that you should use exterior paints indoors on the assumption that it is "tougher". In fact, some of the highest-grade exterior paints can be worse to use indoors than a lower-quality interior paint.
Spring is a good time to paint fences and the exterior of your home, especially wood surfaces. This way, they will be protected from summer heat and sun. Wood decks should also be sealed once a year.