Spend time in the company of soldiers and you notice one thing: they know how to travel.
Their laptops are brimming with films and music. And they can sleep anywhere at the drop of a hat. It's a skill I rather envy as we take off from RAF Akrotiri on route to Tallinn. Within minutes half the plane seem to have nodded off.
Corunna Company are heading to Estonia to take part in the country's biggest exercise since the Cold War. A two hour coach journey from Tallinn brings us to an army barracks near the eastern town of Johvi. The Russian border is just 20 miles away.
Estonia, like its larger Baltic neighbours Latvia and Lithuania, was once part of the USSR. Hidden behind Churchill's famous 'Iron Curtain'. But a quarter of a century on from the fall of the Berlin Wall it's now part of NATO.
Located on the Gulf of Finland, Estonia has a population of 1.3 million, a few hundred thousand more than Birmingham.
Its regular army numbers just 3,000 troops but it has a much larger reserve thanks to conscription. Young men between 18 and 27 have to serve either eight or 11 months in the army depending on the branch they are sent to.
Women can now sign up too, but unlike the men they're able to leave the army after a few months if they wish. Once completed, conscripted soldiers join the country's reserve forces which number tens of thousands. Estonia also has a Defence League, a volunteer paramilitary force similar to the Home Guard.
Corunna Company, along with a small number of soldiers from eight other NATO nations, are here to test these various military forces; to play the bad guys and see how well these Estonian reservists can be mobilised to fight off a border incursion.
Nobody here is talking directly about where that pretend threat might come from. But for these small Baltic states events in Crimea have focused minds. A young Estonian officer points out that this year's Exercise Siil is four times the size of the last one.
Alongside 2 Yorks will be a company of US armour with their Abrams tanks. Overhead four RAF Typhoons, which are currently based here in Estonia, will be offering air support. Alongside them, American A10 'tank buster' aircraft. Designed in the 1970s to destroy Soviet armour, the US Air Force is reportedly bringing some back to Europe in light of events in Ukraine.
The English translation of 'Siil' is hedgehog. On the parade square outside Johvi barracks 2 Yorks are presented with special arm patches to mark their involvement. "A hedgehog has many spikes in its armoury," and Estonian Captain tells them,"And you are a very important spike."
Alongside the NATO nations there's one other, perhaps suprising, country on the invite list: Russia. The size of the mobilisation contravenes a long-standing agreement between Estonia and Moscow. It means Russian observers will be here on the ground watching this exercise.
For 2 Yorks this is a chance to return to basics. Less than 12 hours after touching down from Cyprus they are 'tabbing' along an Estonian road heading into the vast forest. On their backs, 80 kilos of kit and equipment.
After a decade focused on Afghanistan, the British Army is returning to a conventional war fighting model, swapping the Forward Operating Bases (FOBs) of Helmand for more traditional Cold War-style soldiering.
For Corunna Company the next two days and nights are spent preparing for the exercise; relearning how to clear an enemy from woodland - what the army calls 'OIWAF' (Operating in Woods and Forests). And despite the drizzle they seem to relish being out here.
This is a country of vast, endless woodland. Enter it and you can barely see more than a few metres in any direction. And underfoot there's a tangle of saplings ready to snap your ankles. Not the easiest soldiering terrain. The saving grace is the peaty earth - far more comfortable to sleep on than damp British soil the soldiers tell me.
As 2 YORKS begin the march back in, a large column of green Estonian army trucks rumble past us heading into the exercise area.
The following day the barracks are a hive of activity - hundreds of Estonian reservists have arrived from all over the country to prepare for the exercise.
As soldiers do the British and Estonians swap stories over a cigarette, comparing equipment, rations and of course salaries. The Estonian's kit is made for the Baltic weather. Smoke puffs from the chimneys of their large Swedish-made tents, each one fitted with a wood burner. And in the dining hall breakfast includes a tin of Baltic herring.
In impeccable English one young Estonian soldier tells me he studied Hospitality Management in Birmingham. He loves the UK, especially London, he says, but tomorrow it's a different matter. There is soldiering pride at stake, both armies keen to come out on top and prove they're the hedgehog with the sharper spikes.
Simon Newton has travelled to Estonia with 2 YORKS from their base in Cyprus