How much to tip abroad: Tips on getting the gratuity right

On holiday, there's one thing that keeps me awake at night: not the feel of the bed or how loud or light it is ... it's how much to tip. That may say more about my neurosis but, still, it's something I worry about getting right.

A recent visit to Sri Lanka amplified this. You might think it's about ensuring you have lots of small units of local currency to hand – but as well as posing an arithmetical headache, I find it a psychoanalytical mind screw not simply solved by a tap of a calculating app. There are many factors to weigh up: what's culturally in keeping? Is the cash relied upon? Is an individual or the staff as a whole deserving? How much can you afford? How much cash do you have on you? Cripes. So many considerations.

So, here we are in this lovely Sri Lankan hotel and my friend asks the manager how much he thinks we should leave in cash for the staff. His understandable response of “it's totally up to you” leaves us none the wiser. “I'd like to be on the generous side of average,” my pal offers. But what's already an awkward deliberation is made more challenging when we twig that a 10 per cent service charge is automatically added to the bill. The meritocrat in me insists we still slip some notes to the kind souls who were especially attentive, then comes a flashback to when I lived in Mumbai, and an Indian boyfriend got angry with me for what he saw as over-tipping a porter, grumbling that this American custom jarred with the local economy.

Speak to Australians about gratuity and it can be contentious – they rightly believe wage structures should support servers, not the whims of the customer.

Fast forward to me in the next hotel unable to sleep, worrying that I only gave the nice guy who served us our meals for a few days a measly few quid. He was part of a team, I'd tipped them all separately, yet he'd seemed most deserving and I'm sure I spotted disappointment in his eyes. In Sri Lanka, the average salary is roughly £380 a month, and I try to convince myself that what is only enough to buy a large Starbucks latte in London is not such a bad extra. I start imagining this chap being the breadwinner for a huge extended family. I feel like jumping into a tuk-tuk in the middle of the night with a few more crumpled 100-rupee notes – even though I've given 300 per cent more than the 2014 edition of Lonely Planet's guidebook indicates is appropriate.

You see, I grew up in the US, where etiquette dictates you leave around 20 per cent as a tip, yet it's a bizarre quirk that this is left to you to figure out as though it's optional. It isn't. All this is to say that when I have to move around lots of hotels – on holiday or for work – it would be great not to have this layer of uncertainty at every exchange with a porter, waiter, housekeeper. Does that sound mean? Maybe I should just holiday in Japan where tips are considered offensive. (Cut to me lying in bed worrying about whether I slurped my ramen noodles loudly enough to be considered polite.)

Juliet Kinsman is the founding editor of Mr & Mrs Smith (mrandmrssmith.com)