Thai electric is same as uk but the risk you take is at airport customs may stop you and charge import duty...i believe it dont matter how old the electrical items are they will still charge i think its to do with you not buying in thailand this was my experience but it may have changed as that was a while ago now
I flew recently on thai from UK... MOREthan £800... if that low season prices then cant afford high season think way more than £1000 ive seen arab airlines £600+-700+ long gone the good old days on Thai before covid £434 but whilst in pattaya the good hotel prices werent cheap anymore either
i believe thats 40k+ a month and 400,000 in bank and you have to be over 55 i think....and you need to factor in compulsary health ins now as well think maybe 20k a month