DO NOT paint! If you must then only use a stain. It has been a major headache having a fence you have to paint. It looked wonderful when it was new. I wanted a white picket fence. It then turned into a green and black fence that has to be power washed and repainted which is more work than we want to put into it. Plus our fence is now rotting and falling apart. I think it's from the moisture that gets trapped from where the paints starts to peel...it rains and water gets in and can't get out. We tried to do everything right....when it was first put up, we gave it time to season, used a primer, rolled it on or used a paint brush for both the primer and paint, then we tried to keep up with the maintainence. It's been the biggest headache!!!
I now love a grey weathered fence. It has its own natural beauty!