Since February 2008 I have been rubbing Lord Sheraton Leather Balsam (£2 to £3 per container - 100 to 200ml) into my leather Boots, jacket and gloves.
I had not rubbed any into my gloves for weeks and have not rubbed the balsam into my leather jeans at all.
My jeans and gloves leaked.
It seems to me that water tends to flow between the stitching (it is mostly cotton)
My Jacket and Boots did not. as the boots and Jacket are protected often the seams are sealed.
In fact I have never had wet feet, this is my second pair of boots - wore out the bottoms not the top - still looks new. I am still wearing my boots - dry and warm. Boots are Aplinestars.
I have not had much success with the gloves - after about an hour they leak if they have been protected. Today they leaked in minutes.
So try Lord Sheraton Leather Balsam costs about £2.50 or could be more as I have not bought any since last year.
I have bought 3 containers since 2008. That I think is cheap and effective protection.