Do I need a TM30 for my 30-day visit to Thailand with a Thai spouse?

Use thai wife id to book in

the owner of where you stay is obliged to do a tm30 for all staying there

Immigration laws require every foreigner to register their place of residence (known as a TM30) within 24-hours of arriving in Thailand.. it is actually the responsibility of the property owner to do it for you.. if you are staying in a hotel or other rented accommodation the hotelier / landlord should do it.. it's a simple process that can be done online at zero cost.. if you are staying at a private residence owned by your Thai wife (or a relative) they are still required to do this.. and failure to do so will result in a fine.. which can hexas much as 1600 baht.. however the reality is that if somebody enters Thailand as a tourist on a 30-day exempt stamp.. and leaves the country within that period without ever having any contact with immigration.. or any other authority such as the police or the municipality.. with the exception of the initial border entry.. then it is possible to come and go without having completed a TM30 and without paying a fine.. but there is always the risk of unforseen circumstances exposing the ommision and you getting fined.. given the ease and simplicity I'd say it's always best to do it.. especially if you intend to return to Thailand in the future.. or maybe want to apply for a longer term visa prior to your next visit.. although it is unlikely to prejudice such an application.. voluntary compliance will always stand you in good stead imo.. compared to potentially having a black mark on your immigration file.. the risk of any serious repercussion may well be minimal today.. but you can never rule out a change of stance in the future.. and if it suddenly becomes a more serious infringement you may live to regret it!

Not for 30 days but if want to stay extra then use the TM-30

Not for 30 days..

A law/regulation requires you to do it.

Practically, you may not have any chance to show/use TM30 if you travel to Thailand only for less than a visa-exempt period, when you don't do anything at the immigration office. Still, the chance is not zero that you could be asked when something police involved happens.

As you own the house, why not just do it online?