changing head shower in bathroom

The stream of water flowing down from the head shower in our master bedroom has been very weak since the day we moved in to our apartment. The shower from other rooms was very strong.
We were told that it was perhaps due to differential pump pressure provided by the PUB (public utilities board) - i.e. those powering the master bedroom was "low pressure".
We accepted the explanation... but alas, as the months go, it dribbles little by little, barely enough to cleanse our body when bathing. As CK put it, the shower in Brunei army camp was even better than ours.

I finally wrote a letter of "complaint" to the management of our apartment, and was informed that the fault might be due to clogging inside the head shower itself.

I am a novice when it comes to plumbing services.
First I ran a check on youtube on how to change the head shower... and it was quite educational. It seemed quite easy to unscrew the head shower.
Bought a small head shower from hardware shop in Eunos, tried to unscrew the old head shower.

Hurdle #1:Discovered to my horror that pipe and its screw was too big for my old spanner. Bought a new (and bigger size) spanner two days later.

Hurdle #2: The unscrewing to release the old head shower itself was quite challenging. There are two rings to unscrew (the first one anti-clockwise, and the second (inner ring) clockwise). I managed to unscrew the first outer layer, but it took me another hour or so to realise that I had to unscrew the inner layer clockwise to remove the old head shower.

Hurdle #3: When I compared the size of screw (to that of the metal pipe hanging from the ceiling), I thought it might be too small to fit in. Hence, I had bought an adapter from the hardware shop the next day (as recommended by the shop owner). But after unscrew the old head shower from the main handle, I found that the adapter was too big for the hanging pipe. After many attempts and "trouble shooting", the problem was solved by removing the adapter --> the origninal screw fit it just nicely to the tapering tip of the hanging pipe. WHAT A DISCOVERY!

It took me almost the whole afternoon to change the head shower. And yes, it is working well with strong jet of water flowing down when I shower!

                                                       TADA... the new head shower!

The cost of this DIY work - new spanner $13, new head shower $7.50, adapter for head shower (which was never used) $2.50. Total cost $23.

 I guessed it is definitely cheaper than getting a plumber to do the work.... but the immeasurable manual work/headaches in figuring out how to get it done ... I guess it is called Life Experience!