If you are only staying a week every couple of months then you should be OK with visa exemptions. If the number of days in Thailand exceeds 150 days or maybe 180 days in a year or you are doing back to back border runs then you will be questioned.
They are looking for patterns of travel and time in the country and if you spend time in your home country. I don't think anything will be reset on Jan 1. You might get in again but you would be much safer after February and getting a METV