The first thing you need to do is ensure a TM30 has been made to register your new address. Maybe your landlord has done this, otherwise it's your responsibility. I would phone or email the immigration you would be using & check their rules, so many office's requirements differ
if on holiday and you only need a sim to call a taxi or check a route low speed and cheap is ok, as majority of planning i do evening before using hotel wifi, each situation is different so great to have a choice
Majority of them are fun and lovely, doing this work as hoping to find a wealthy foreigner. Talk to them, ask them take you to a restaurant they actually save you money too