Fitting timber windows into timber frame with weatherboarding

[Notch7]

Is a lead tray required on the underside of the window?
(Im not talking about. windows which have lead flashing dressed down noticeably over the weatherboarding -which is a visual detail visible on some period houses)

I'm never sure whether this gives any benefit or not.

I have seen it and done it where the lead is clipped to the underside of the window before fitting and turn up with a small lip to the inside, preventing any water running inside (limited benefit unless the lead is dressed at the sides to form a 3 sided tray.

However what is the actual benefit, if any?

Windows have a cill projection with a drip.

 

[Gazman16]

I'm more of a PVC guy but have ripped out enough old timber windows to say the old lead trays really do make a difference to protecting the timber frame underneath.
I'm guessing in the long run lack of painting maintenance is when the moisture gets through the window to the structure behind but also IMHO most modern wood is crap and very porous.

I was looking into it a little while back for my timber framed out building. PVC windows but was looking at extra protection for the frames.
Americans are using adhesive tapes similar to what you would use on ducting or polycarbinate ends.