Do I get an extra 15 days in Thailand by visiting Laos for 4 days, and how many times can I enter Thailand in a year?

The general rule is that if you leave Thailand and re-enter after a short trip, you may receive additional stay time, but the amount of time granted (usually up to 30 days) can vary depending on your nationality. Generally, travelers are allowed to make a border run twice a year by land. Additionally, there are options like visa extensions for those who are married to a Thai national.