Andrew Barratt, my lodger, is in the kitchen preparing parsnip and Parmesan soup. My younger son, Cato, 29, stands next to him discussing the meaning of life. Olly, my husband, pops in to offer the chef a glass of wine.

Down the hall in my living room friends, and my elder son, Zek, 33, and his wife are gathered around the long table anticipating this “family” dinner, to which Andrew has invited them. Andrew has been our lodger for 23 years, and has moved house with us twice, becoming by now an honorary member of the family, even celebrating his 50th birthday with us a couple of years ago.

Why has he stayed so long? He parries this question, murmuring in his droll way about it being “an easy place to be. Quite friendly people around . . .” We’ve had a few contretemps along the way of course, and on the days I just don’t want to communicate with anyone, the sight of my lodger bright-eyed and bushy-tailed turns me into an instant grouch. But we have forged a successful lodger-landlady relationship.

At a time when more and more people are considering lodgers to help to keep their finances afloat, understanding what is entailed is a good idea. Lodgers occupy a furnished room in your home but live as part of the household, sharing your kitchen and bathroom. Revenue & Customs smiles on this arrangement and allows you to earn £4,250 a year tax-free (£2,125 if letting jointly) from lodgers.

The idea of someone living in your home can be daunting. Usually this is because the lodger doesn’t understand about boundaries. Andrew is respectful of my space and enters only when invited — unlike a friend’s lodger who joined his landlady and landlord in their living room almost every evening, announcing: “Thought you’d like a bit of company!” And although Andrew’s room makes the den of Harry Enfield’s Kevin seem salubrious, I know that it would be intrusive to barge in and sort it out.

However, I’ve had words with Andrew over encrusted cooking pots in the kitchen, a forest of food crumbs on work surfaces and coffee grains in the sink. To say nothing of his lusty singing, which shakes the timbers of the house. Happily, however, maturity has reformed him and these days he is for the most part more user-friendly: he bakes our family bread, grows tomatoes on the roof and torments anyone who does not observe a strict environmental code.

In turn, Andrew, a film production manager, has balked at my insisting that the kitchen must be re-arranged to my own plan, and been less than pleased when I’ve finished his pesto — protection for food in a communal fridge needs to be sacrosanct, I have learnt. Andrew also protested (with justification) at a guest of mine who took over the bathroom for an hour when he needed to get to work.

We’ve been lucky — we knew little about Andrew when he came, and that was foolish. His brother had been lodging with us, and Andrew just took over the same room when he left.

So would I recommend taking in a lodger? Yes. Aside from helping with bills, he or she can be a delightful addition, offering friendship, a new sense of life after children have gone, and be someone up for a bit of give and take (he walks your dog and you water his plants when he is away).

It won’t be a perfect arrangement 365 days a year, but if you can do as we do and share a laugh, cook an impromptu supper together, pop out to a film and watch your lodger getting on a treat with your children, then it seems a pretty good deal.

HOW TO FIND A JOLLY LODGER

• Choose your lodger with care. The website landlordzone.co.uk advises obtaining references and credit checks, and there are formal lodger agreements that offer some protection to both sides (available from lodger-agreement.co.uk).

• When a prospective lodger comes to view the room, treat it as an interview. Explain how things work and any house rules. Give the lodger a chance to ask questions — it’s far better to learn that your lifestyles are incompatible now rather than later.

• Bathrooms and kitchens are potential flashpoints and both sides need to be clear what is expected, and how it should be achieved.

• Fix individual times for using the bathroom and for cooking an evening meal — at least to start with.

• Both you and your lodger should be honest if you are unhappy about any aspect of the arrangement — many successful compromises have been forged this way.

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