This would include window frames and any existing painted surfaces.
Exterior paint must be used as paint designed for internal works will not stand up to the weather.It is not always a good move to burn off all old paint as this protects the wood. However if the paint is badly damaged i.e. blistered by the sun then it is necessary to burn off and treat the timber with a linseed oil to put some life back into it.
If the paint is in good condition it is usually only necessary to rub it down to give a smooth surface and remove any loose or flaking paint.
It is not wise to paint in extremely hot weather as it will cause the paint to blister and before you know it will be falling back off!
The same applies to extremely cold weather.
Also remember that a wind when painting will cause the paint to sprinkle any cars and other properties that are close by so you could end up with a bill for cleaning !
Even if there is ideal painting conditions it is wise to move cars ( ask the neighbours to do the same) as accidents do occur.
Generally speaking you will need to apply one undercoat and one top coat. However, if you are covering a dark colour with a light colour you may well require one more top coat. Bare wood will require a primer, this is a special coat to seal the wood and get it ready for painting.
Also remember when painting windows you may have to allow to remove and re run putty that has dried out and cracked over the years.
Metal gutters will require re painting along with the rest of your pre painted surfaces. These will need to be rubbed down with a wire brush to remove any rust and then touched up with a metal primer before applying the undercoat and top coat.