Leather does not need 'conditioning' per se. It should be kept clean and then protected with water based products that will inhibit dirt and oils from penetrating the leather (these are what do the damage to leather). Moisture will keep the leather in good condition and it is important not to use any oils or waxes on your leather as these may sit on the surface (depending on the type of finish) and attract more dirt and oils.
Conditioners are generally at best harmless or at worst something that could damage the finish on the leather.
Protect your leather from new with a good water based leather protector and then clean little and often with a water based foam cleaner or maintenance prodcut and your leather will remain clean and in good condition for a long time. A protector will also inhibit dye transfer from clothing and will make ink and stains easier to clean off.
Hope this helps