Radio play lists. How do they work?

I remember hearing a while ago that radio stations don’t have to pay royalties on a record if they play less than five seconds of it, which suddenly explained to me why ‘Name that tune from a five second clip’ questions are so popular on phone in quizzes and why there’s so many ‘We’ll be playing the whole of the record that this five second clip is taken from’ teasers.

One other thing I’ve noticed is that sometimes an older record that has long since dropped out of the charts will get played several times in one week, then forgotten about for months.
Something like Crazy, by Gnarls Barkley, or I like the way you move, by Bodyrockers, both big hits a few years ago, but not normally on current playlists.
I can go for weeks of not hearing them, then they are on three times in one week, then they disappear again.
Is it just me, imagining I can see a pattern in the randomness of life again, or do radio stations get some sort of bulk deal on royalties, a bit like renting a video for a week and watching it every night until you have to give it back?

I think they play a previous record from whomever when a new one is due

I think it depends entirely on the station. Commercial stations, I believe, have playlists created and sent out, where they have to play certain chart records so many times a day, certain golden oldies, the same.
BBC stations have playlists decided by a group of the producers and DJ’s sitting around and discussing what’s new, what is in the charts, climbing and dropping, and so have A, B and C lists, with DJ’s having some choice of their own.
6Music has playlists, but they’re not constrained by the charts, when they get new releases, they again have A, B and C lists, from what I understand, so new tracks from popular artists will get heavier play, like a new Arctic Monkeys, for example. There are also certain older tracks that get regular play, and all sorts of random stuff the DJ’s can play that suits them.
That’s my sort of understanding of how they function, and it’s why I favour 6Music, there’s always completely new stuff being played every day, but not all of it gets played regularly.
Shazam gets a lot of use for that very reason.
I’m happy to be corrected on this, it’s not something I’ve ever looked into in depth.

The A/B playlists sometimes get a mention on Radio 1, Moyles used to mention them occasionally when he disagreed with a track that had made it on to the A list (meaning it had to be played every two hours!)

6 music also seems to have some sort of system in place which prevents artists being repeated in a certain time period – on several occasions I’ve heard a dj saying they were going to play “artist x” but “dj y” played them in their show already

Although 6 Music have been playing the latest Courtney Love tune incessantly and what seems like at least once in every show during the daytime. Not a bad tune, but I’d prefer Give Me Chocolate by Babymetal 😉

I’m sure my local radio station has a playlist of about 10 songs usually including Adele, Bruno mars, Take that, Olly murs and other similar rubbish. Once you’ve been listening for about an hour you get to hear them all over again 😆

I have it inflicted upon me at work 😥

Even if to the best song in the world you don’t want to hear it over and over again.
Virgin played that bloody Breakfast at Tiffanys every show for at least 18 months. Why? Surely the Djs get sick of them as well.
Edit, I’m sure I read that the average radio listen is 20 minutes ,so they want to be sure that you will definitely here the latest shit record.
Also , can Heart legally claim to have ” the greatest music variety” ?