Updated: Jan 16, 2019
Wooden joinery requires maintenance every few years but in my opinion it looks great. If any paint is chipping you need to make sure this is stripped and re painted to keep the elements out. I find the North facing windows get hammered so keep an eye on them as you dont want rotton window frames.
Steps you can follow
Waterblast or clean of all flakes and dirt
Sand to a smooth finish
Undercoat with exterior undercoat. I prefer to use oil based still.
Coat with your desired colour to finish (2 or 3 coats)
The end result is always very satisfying if you do it yourself. Yes, the process takes many days of hard work so I suggest you plan ahead and either go ahead and do all you need or break it into segments.