Thanks for the Blackrock recommendation. I ordered some, and have started weekly treatment of my "everyday" boots.My husband is one of those "leather people" lol so I asked him. He suggested Kiwi brand mink oil, because it also contains lanolin and silicone for better water repellancy. It will darken the boots some, and if used properly - NO, it does not harm the leather or stitching. Once you apply the oil, if you can let the boots sit in the sun to warm up - warm leather will absorb the product better.
Non-locally, I highly recommend a product called "Blackrock." That stuff is amazing. You can usually find it on ebay for around $10-$20 for a container that will last forever. It is also excellent for use on antique items like flight helmets and old A2s.
I had been using Kiwi mink oil. It definitely darkened the boots. I probably would have stayed with Kiwi, but it seemed to attract and hold dirt. Every so often I would need to do a significant saddle-soaping, and that still didn't get all the worked-in dirt out.
After I got the Blackrock, I again saddle-soaped and let the boots dry overnight. Then applied the Blackrock as directed. Wiping down with a paper towel (as directed) took off a significant amount of dirt, and more comes out each week when I repeat the Blackrock treatment.
Definitely a satisfied customer. Thanks again, fortworthgal!