A very good Q, with no straight answer
In the UK, you can just fly with Pooleys, because it is pretty accurate. It's what I do. There are two reasons it is accurate:
1) The UK AIP is of good quality, and Pooleys get the basic data from there
2) Pooleys is widely used in UK GA so errors get picked up
3) As said above, Pooleys covers unlicensed fields also
Abroad, things are a lot less good and the "pilot guide" publications, where they exist, are much more variable in quality. But then GA activity in the rest of Europe, with the exception of Germany and France, is much lower anyway.
What one consistently finds, with all aviation databases, is that their quality is related to their usage in that particular geographical area...
However I also
telephone an airport I am going to, before going there, just to check they are open, have fuel, etc. Very quick and easy. Some are PPR and the phone call covers that, too.
Plan the route
Get notams
Get airport data
Phone the airport