Leather bags can last years and even decades, and longer than man made bags such as PU or PVC leather. They also smell nicer and need little upkeep. If you have looked for a conditioner on the market, you would have noticed you are spoilt for choice. There are also water repelling products and various types of oils and balms.
All work well but you do not need to pay a fortune and you can always use your scent free moisturiser. Like our skin, the bag will feel softer after a good moisturise. I also use the same leather conditioner for my saddle, bags and leather car seats.