by davekeiller » Fri Mar 15, 2019 9:56 pm
It's worth investigating to find out if the boots are, in fact, leaking or whether dirt is clogging the membrane and causing you to get wet from sweat (or water is being funneled in from above at the ankle). If that's the case then cleaning (inside and out) and applying a suitable waterproofing product will likely resolve the issue. Try filling the boots with water and leaving them overnight - if they're still full in the morning then they aren't leaking.
With leather boots, the leather is waterproof but only up to a point, and water will eventually soak through. Membranes provide an impermeable barrier to prevent this happening, although some suspect that this also allows the manufacturers to use cheaper leather. It's generally regarded as being important to use wax on leather boots as this helps to replace the oils in the leather which stops it drying out and cracking and also maintains water repellency. Nikwax and Granger's claim that their products are formulated such that it's no longer possible to "overwax" boots and damage the leather, although this was possible in the past when using old fashioned dubbin. I wouldn't bother applying anything prior to first use of the boots, as they'll have been treated as part of the manufacturing process, and the point of applying something is to restore this after exposure to the elements.