windows need painting every two years

[kofi2003uk]

hello ,
bought a house a few months ago and the previous owner told me the windows needs cleaning and painting every two years.at the moment they are painted redish brown.
my problem is i am not sure what type of wood it is.just noticed that there is a bit of rot on the outside and when it rains, some water leaks through the wood although it is double glazing.
i got wood filler from b and q and filled some of the holes between the glass and the wooden frame on one of the downstairs windows. that solved the prokblem on that window.
any advice on what to do next? if i get all the windows done with the filler , will that solve the problem.any recommendations please?

 

[masona]

I has this with my mum bay windows and the brown stain paint over the years made it too dark after a few coats, I'v stripped the old paint off and I was amazed, it was mahogany timber, I've used tung oil to bring the natural grains of the timber, it's so easy to wipe it on for the future,