The cost of a family holiday starts creeping up long before you’ve packed a suitcase. You spot a bargain flight, click through to book, and suddenly you’re faced with a long list of extras: checked bags, seat selection, priority boarding, airport hotels, lounge access, in-flight meals and more.

As a family travel expert and mum of two, I’ve learned that not all add-ons are created equal. Some genuinely reduce stress and improve the travel experience, making them worth every penny. Others can quickly add hundreds to the cost of a trip without offering much value in return.

Here are the flight extras I always consider spending money on – and the ones I’m usually happy to skip.

Checked luggage (sometimes)

Sharing a big, checked-in suitcase can be a sound investment (Photo: Oscar Wong/Getty Images)

This surprises people because I’m a big advocate of travelling light. For a short city break or a week’s summer holiday, our family can often manage with cabin bags alone.

However, there are times when checked luggage is worth every penny. If we’re travelling with bulky winter clothing, for example. But even then it’s still worth considering if we really need a check-in bag for each member of our family – often one large suitcase between us is enough.

I always check the policy of the airline we’re flying with, and make the most of any free items for infants and children we’re entitled to. Usually you can take a pushchair, plus an additional item such as a car seat or a travel cot, free of charge, even if you haven’t paid for checked-in luggage.

I also factor in the cost of airport shopping. If avoiding a checked bag means buying expensive toiletries at the airport or paying for laundry abroad, the savings can disappear quickly.

The key is doing the maths before you book rather than automatically adding luggage to every passenger, as well as doing some clever packing.

Seat selection

If I was flying solo, or my children were older, I wouldn’t bother paying to choose our seats.

But when travelling with younger children, it’s one of the add-ons I prioritise. While airlines generally aim to seat young children with an accompanying adult, this can often be across the aisle or in the row behind. Also, having another adult sitting in the same row can make managing little ones a lot easier. Paying to reserve seats removes uncertainty and avoids the anxiety of wondering where everyone will end up.

For longer flights, being able to choose seats that work for you – such as seats in the bulkhead where you can then request a bassinet for infants (a game-changer for long-haul), or being close to toilets, can make a noticeable difference to your comfort during the journey.

Airport hotels

This is probably the travel expense that gives me the greatest return.

A 3am wake-up call with children can turn the first day or two of a holiday into an endurance test. If we have an early departure, staying at an airport hotel the night before often means an extra hour or two of sleep, a more relaxed start and eliminates the risk of getting caught in traffic or roadworks.

When you factor in fuel, airport parking and peace of mind, it can represent surprisingly good value.

The add-ons I don’t pay for: priority boarding

This is one of the easiest extras for me to skip.

Families with young children are often invited to board early anyway, and even when they’re not, I don’t see much benefit in sitting on the aircraft for an extra 20 minutes.

Unless priority boarding comes bundled with a larger bag allowance, I usually save my money and let my kids burn off energy in the terminal before they have to sit down for a few hours.

Airport lounge access

These can be lovely, but they’re not always family-friendly. Unlimited food and drinks sound appealing, but with children you tend not to have long enough to sit down and make the most of it.

For the cost of lounge access for a family of four, I can buy a decent meal in the terminal and still have money left over. During peak holiday periods, lounges can book up fast, meaning unless you’re organised, it’s not an option anyway.

If I have access through a membership scheme or travel card, I’ll use it. But I rarely pay.

Overpriced snacks onboard

Packing your own snacks reduces costs and offers control and flexibility (Photo: Dobrila Vignjevic/Getty Images)

I’ve learnt the hard way that hungry kids and travelling is not a good combination. Once you’re onboard the food selection is limited and expensive.

I’ve learned to pack our own snacks before we leave home. Cereal bars, crackers, crisps and a few sweet treats cost a fraction of what we’d pay once in the air. It also gives me more control over what everyone eats and when.

Anyone who has travelled with children knows that their frequent snack requests rarely align with the airline’s in-flight service schedule, so having familiar snacks on hand can be a useful tactic to prevent boredom and mid-flight meltdowns instead of waiting for the trolley to pass by.

I might occasionally buy a coffee or bottle of water if needed (or treat myself to a glass of wine), but I don’t see the value in spending the money when a little preparation before travelling can save a significant amount.

Jen Carr, family travel expert and founder of The Travel Mum, shares the best affordable holiday deals for families throughout the week. Jen’s new book “Yes You Can Travel With Kids” is available published by Dorling Kindersley