If you stay in Thailand on the basis of a Non Immigrant Visa, class “O” or “B” and you do not qualify for a one year extension of this, you will usually have to make a so called Visa Run or Border Run every 90 days, until your visa is expired.
There are a lot of people, who make their stay in Thailand dependent on whether they will get a one year Visa or not. I think Thailand is loosing quite a lot of retirees every year due to the existing prerequisites for a one year visa or a one year extension.
But in fact, there is not much to worry about, if you have to make a visa run every 90 days. At least in every tourist place in Thailand, like Bangkok, Pattaya, Phuket or Samui, visa runs are well organized and bring foreigners with air-conditioned busses and sometimes even by boat to the nearest border.
There, you will have to exit Thailand, enter the other country, turn around and exit the other country and then reenter Thailand. That means, you will get 4 stamps in your passport on every visa run: Exit – Enter -Exit- Enter!
After this procedure, the same bus will bring you back to the place in Thailand where you came from. Normally, a visa run by bus will be done in only one day and the companies do this almost every day.
But there is another option for a Visa Run. How about a shopping trip to Singapore or Hongkong? Budget Airlines like Air Asia or Tiger Airways connect at least Bangkok, Phuket and Krabi with other interesting destinations in the region. In case of Bangkok or Phuket, you can even do it within one day but it might also be nice to stay somewhere else for two or three nights …
So, don’t take the visa runs in Thailand as an obstacle, just take it as an enjoyment and you’ re right. Enjoy your stay in Thailand.