How do I refurbish this wooden mail post? Either with wood or paint.

I would try painting it with chalk paint. You could paint it in gray, black or a pretty blue.

It looks to me as if it is on a lean towards the road. If it ever were to fall over causing an accident or injuring someone, as it is on your property, you would be liable. Is the post reinforced with concrete under the surface of the soil at the bottom? If not, then it needs to be, in the same manner as fence posts.

Definitely paint the post a brighter, livelier color. Your mailbox post gives a first impression to your house, and can affect its curb appeal.

If you were to paint the numbers with glow-in-the dark paint, they would be visible not only at night, but in foggy or stormy weather also.

The flag is not displayed properly and is partially concealing the number. Even small flags should be mounted so that their poles are straight, not on a lean. If you still wanted it on the mailbox post I would put it at the very top.

I would use a good quality exterior stain to protect the wood. They normally contain water repellents and ultraviolet light absorbers that help protect the wood from the elements. You can use either an oil- and water-based version and it will allow that gorgeous natural wood grain to shine through.

Easiest would be Preserving Stain, but Painting with Garden Shades Paint would be good too. Or Prime - Undercoat - the Topcoat with a Gloss Paint.

We just re-done ours and used Barn paint only because we had it leftover from another project. But I do like Flipturn's idea of using glo-in-the-dark paint. When I get that done will post a pic

First of all I would use a deck cleaner to see the natural wood. Then I would decide if I wanted to paint it or if it is good enough condition to stain and/or seal it. Good luck.

Powerwash than buy 2 in 1 paint with primer

You're welcome. That is sensible to do the work all at once. Even if it takes a little longer to complete, that way you have all the mess out only once, and if finished properly, the attractiveness will last much longer.