I went in first time buying my initial vape and oil was good. After the fact I was getting burnt oil within a day turning yellow. I initially let it go and bought more oil and cartridges. That did not help. I bought two more cartridges and they still burnt on the cartridge. After the fact thinking it was either the cartridge or oils I bought another set of cartridges and oil and still the same thing happened. I went into the store wand explained my situation. As I explained my situation the employee basically told me nothing was wrong and my pod and I was the issue. I went to a different store and bought the same exact oil and cartridges and so far haven't had a problem. These guys are either selling fake oil or are selling expired stuff. Never have had a problem anywhere else.. be careful