In reply to bouldery bits:
Sorry for delay - just noticed your post.
If the leather is really badly affected by time, neglect, or say detergent use, neatsfoot oil is remarkable stuff. I only use it on the older boots to rejuvenate the leather.
Its messy but effective so use gloves, protection for floor/worktop, and you will have to give them plenty of time (days) for it to soak in fully and be semi dry.
If not too bad, or normal soaking/drying use, you can use a small amount of neatsfoot but I much prefer liquid nikwax - the old really waxy stuff - but unfortunately this has not been sold as far as I'm aware for years. Nikwax went over to the aqueous wax and this just runs off and does not really soak in. I've still got some left to do me for a few years yet
! It is easy to get into all the stitching and parts of the boots that solid wax can't.
Other than that as regular maintenance nikwax or grangers solid wax is my preference for light general treatment. Personally don't like the thin liquid waterproofing treatments that are about.
Hope that helps.
Post edited at 21:56