If you apply the cream once every 6 months you are taking great care of your couch assuming you use the right amount of cream as instructed “How much Leather Goodness must I use?”.
My advice is always to do it properly as instructed and then again in 6 months. You cannot really apply too much cream at once as the leather can only absorb so much at a time and any excess cream that is not absorbed can just be wiped off with a dry cloth. You can however put the cream on too often causing it to turn darker as the hide is taking in too much oil. I suggest subscribing to our 6-month reminder email which will automatically update you every 6 months when you should apply the cream to your couch again. 550 millilitre tubs are perfect for lounge suites, 3-seaters, 2-seaters, and single chairs. 300 millilitre tubs are enough for a large 3-seater couch. 150 millilitre tubs are great for bags, shoes, belts, jackets, and etc.
Depending on how dry your leather is will determine how much of the cream your couch absorbs. You could need slightly more if your leather is very dry and slightly less if your home is in a cooler area where the couch does not dry out as fast.