Is heating maintenance really worthwhile?

Briefly for understanding:

We have a gas boiler with a combination storage tank for hot water. It was installed and commissioned in November 2015. It was inspected by the chimney sweep then and re-inspected by him in 2017 (every 2 years). When the water pressure of the boiler was now only just above 1 bar (about 1.1), I wanted to have water refilled. I was told not to do this alone because apparently one should not use regular tap water for this. Also, the pressure should not fall below 1...

While reading on the internet, I noticed that many have their boilers serviced annually and these tasks are done during the annual maintenance. From what I have read, it is apparently a must and should definitely be done every year. So I picked up the phone and booked a maintenance appointment with a local plumbing company. This costs €95 net + material extra...there was even a maintenance contract offered so that these take place every year from now on.

Now my problem:
The plumber came shortly after 11:30 to service the gas boiler for the first time in 3 years (my wife was at home). I arrived home at 12:00 (I took an early lunch break on purpose) – he was already gone. According to my wife, he cleaned some dust...no water was refilled. I then called the company again and they checked...at 1.1 bar you don’t need to refill...

The invoice was already in the mailbox the next day...about €113 gross. For 20 minutes of dusting...now I’m starting to doubt the sense of annual maintenance...how is it handled with you?

Of course, you can refill the water yourself using tap water. Which isotonic miracle drink did your plumber want to use?

Yes, maintenance should be carried out regularly every year. Otherwise, there is no warranty. Like with a car.

I would only enter into a maintenance contract with a company that I know and consider to be confident and professionally competent.
I believe he was at our place for half an hour. Dusting off doesn't take 20 minutes, so he probably did something else, like checking seals, etc. Yes, most things are only checked during maintenance, and you can count yourself lucky if nothing is defective, and the specialist company charges a higher bill.

Of course, you can refill the water yourself and use tap water for that. What isotonic miracle drink did your plumber want to use?

When refilling back then, the plumber came with a water cartridge... I found this about it:

"....For these reasons, manufacturers of heating appliances require low-salt, alkaline water that complies with the specifications of VDI 2035....."

Yes, maintenance should be done regularly every year. Otherwise, there is no warranty. Like with a car.

I would only enter into a maintenance contract with a company that I know and consider confident and professionally competent.
I believe he was at our place for half an hour. Dusting doesn’t take more than 20 minutes, so he probably did something else, like checking seals etc. Yes, most of the time during maintenance only checks are done, and you can count yourself lucky if nothing is defective and the specialist company charges a higher bill.

It is a new build and we previously rented. So I have no experience with plumbing companies from our area. I then asked around among acquaintances and trusted their experience.

And the thing with the maintenance contract and the price is probably like that with all companies in our area...

Hello,

we have often had threads here where people wondered about the 100 million KWH hours consumption.

Do you go to the dentist for preventive care?

Do you have your car inspected?

then get it done. Often some filters need to be changed, and it is common to round up to full hourly rates. He also had travel time

There is also quite a bit (!) of white combustion residue that is knocked out as powder, and various wear parts are (as a precaution) regularly replaced.