the first thing you need to realise is what exactly you are paying him for.
By your description above it sounds like you are simply engaging him to do routine site inspection for the purposes of releasing stage payments and certifying the work at the end to state its in compliance with planning permission and building regulations.
You must understand that this engagement is not any form of 'supervision'.
I will assume you are paying him around €2000. A supervisionary role may cost 2-3 times that figure. If you are paying higher, then you should get a greater service.
Its generally up to you to let him know when a particular stage is finished (blockwork, roof etc) and then he visits the site to ensure what ive stated above, that the work is in compliance with planning permission and building regulations.
This generally does not extend to such things as best practise, best workmanship etc. These issues are included in a 'supervision' engagement.
generally if you havent heard from him after a visit you can take it hes happy the work complies, if it didnt then you would hear from him, as he did in the previous stage.
My advice would be to use him as much as you can. For advice on insulation and energy conservation etc, as this is part of the building regs. Generally, the 'inspections' engagement doesnt include construction advice, but try to get as much out of him as well.
Remember that out of his fee he has to pay professional indemnity insurance, which is the main issue. He will take responsibility for the compliance of the dwelling in accordance with planning and building regs.