@Tod ********
Hi Tod, thanks for your kind answer and info.
My intention is to get a multiple re-entry permit and be traveling frequently (leaving Thailand for a month or more, visiting Italy and China where I have families living, but returning regularly and frequently to Thailand) and therefore I would be leaving that hotel after a month or 2, maybe 3, and maybe even change hotel when I come back to Thailand.
So I would in any case not make a commitment with a hotel longer than 1 month at a time.
Just to clarify better, in this case a hotel will issue a letter indicating I will be going to stay XXX months, ie. longer than the months commitment?
Or, would a hotel letter indicating I will be staying with them 1 month (at a time) be sufficient for immigration?