I found a great older condo and pay rent in advance per year (officially it's per month, they love me for paying a year in advance and gave me extras like free internet, new tv, fridge etc. normally this cost each 500/m extra), no plans to move out within the coming 5 years. Only two things that I don't like are the fixed king size bed - a wooden box with a huge wasted storage space underneath and the lack of a kitchenette. I have a technical background and breaking out/reinstalling the bed is easy for me. Plan to buy a ready made (mobile) kitchenette and put it or near the bathroom (water/waste water) or near the balcony. Any tips on how to handle this the best way with the company who owns the residences? Or just do what I want because I stay here long time anyway? After all I won't break out any concrete, it's just an outdated bed. Advise/ideas welcome.

Do nothing without condo owners approval.

You also need to keep in mind doing work of type proposed might create problem with condo management since you want to do yourself. Remember some managers tightly control any work done in building so they can generate extra pocket money.

Are you dealing with the actual owner of the condo unit, or a rental rep/agency? If the former, and you have a decent rapport, it might be worthwhile to see if they'll split the cost 50/50 with you with the understanding that you leave your improvement in the condo when you leave and that it won't be an issue with getting back your security deposit.

I have friends (multiple) who have made similar arrangements with their landlord/owner for installing/replacing air cons and other condo upgrades.

This condos are owned and rented by the same owner pretty much like a hotel. I think I'll show them my ugrade plans designed on paper incl. photoshop of the result. Deposit is only 10k that's not the problem.

This condos are owned and rented by the same owner pretty much like a hotel. I think I'll show them my ugrade plans designed on paper incl. photoshop of the result. Deposit is only 10k that's not the problem.

Sounds like you are staying in an apartment and not a condo. An apartment has a single owner for the whole building. A condo building has different owners for the many units in the building.

Yes, invest a million baht to improve the room and then get thrown out, with deposit forfeited... ?

Just Do it a little at a time the owner will love it and so will you. Being doing it for 18 years not my room the Thai owner has nothing to lose except me.

I would always check with the owners first. It's their property. If it's an object which is mobile and does not require fixture to the floor or a wall, you would not require permission. Breaking up an existing bed certainly does.

I've done a few small modifications in my condo apartment. I made sure I explained very clearly to the landlord's agent and the landlord what I wanted to do. No problem.