'None of us is black and white in nature,' says Ingrid Collins, 'which means we can never find a perfect match in one single person. We all have different aspects of ourselves that we need to feed.'
'Sometimes we need a frivolous chat with a friend, while other days we prefer a deep, serious conversation.'
One friend is not enough
'Never expect one friend to fulfil all your needs,' agrees Linda Blair. 'Try to think of yourself as an onion - each one is different made up of lots of layers of differing thickness. People are very similar - we're all unique and need different things.'
And Linda doesn't agree that we need a certain number of mates. 'Some people are more outgoing than others and naturally amass more friends, while others can quite easily get by with 5. It's all about the level on which you connect with someone and how much intimacy you share with that person that marks them out as a friend.'
How do you lose friends?We've all known people who start to annoy us so much that you wish you'd never bothered in the first place.
So is it OK to get rid of friends? 'It's definitely useful to do some emotional stocktaking once in a while,' says Ingrid Collins. 'We love our friends and, although it's slightly different to a partner, if we no longer feel that love, there's really no point in carrying it on.'
But how do you, to put it bluntly, get rid of someone you no longer want to be friends with?
'You can have to be honest,' says Ingrid. 'Tell them that you're going to have to stop the relationship - just try to be diplomatic about it. Say that it's not working any more for you and that you're too busy and don't have the time to commit to it.'
It may sound harsh, but ultimately you have to think about friendships as you do a romantic relationship and end them if they're making you unhappy or your heart's just not in it.