I would say you'll feel if the frequency is busy or not.
Say minimum and controllers will ask what they need (depends if they have a radar or not, or if they have your flight plan or not)
I work in a french approach ...I hope you'll fly there
We like to have " XXXXX, Pa28, from Luton (ICAO code helps!) to your field, approx ground position, squawk, altitude" then we see you on our radar and that the most important for us.
Then we'll ask "what's your desired routing, when do you want to descent, do you like gladiators...
and so on.."