Down in the Channel Islands we have a number of problems with VFR filing or not in some cases.
If you are only a VFR pilot in my opinion is it not best to file on the day of flight as the met can change a lot from a forecast 48hrs before going and some pilots do not get the latest weather before getting into the air.
We have had a number of flight plans where people do not cancel if they do not go, In France if you have not departed after youd planed etd they will automatically canx plan.
There are the laid down requirements for filing of Plans in one of the CAA publications.
Flying more than a distance from your departures point,
Crossing an International boundary,
Crossing over water,
Entering certain classes of airspce I.E. Class A for one.
This is just some of them.
More and more pilots depart from farm strips and just blast off without any notifaction to anyone one, but it is for there safety that filing a plan, activating it and clossing it are all safety issues.
There have been crashes where pilots get airborne and dont activate there plan and on route have a problem and may lead to loss of live and no one is expecting them so no search and rescue airborne.
In the Channel Islands you cannot depart with out a flight plan but the amount of aircraft comming in to the Channel Islands landing or transiting without a plan the numbers are increasing.
Maybe some pilots have not been tought who to file an airborne flight?
If you get airborne without a plan in the system file one with an ATC unit and get it activated.
Always carry a blank flight plan with you as you will find when filing an airborne plan it makes it easy for the ATC unit.
Find out telephone numbers of parent ATSUs a file a plan over the phone the activate with the F.I.R. when airborne.
Filing flight plans do help to save lives if any overdue action need to be taken if you ETA is out by a long time get it updated.
In Jersey a number of years ago a Cherokee filed a flight plan from Beligum taking one hour thirty minutes another Cherokee filed a flight plan taking two hours thirty the second one was the correct time so if the first aircraft got airborne without ATC noticing the wrong elapsed time overdue action would have taken place after ETA plus 30 minutes.
So every VFR pilot must act in a thoughtful way and respect others.
In France they can be very hot on overdue aircraft and the cost alone so beware.
To sum this up File a plan at the correct time after checking the latest weather.
Activate it,
Do- not forget to close it when you arrive this only applies if no ATC at desternation.
So all in all happy and safe flying.
Crossing an international boundary,