Doogie

A friend of mine has owned his glanza the last year and a bit never any trouble and only recently passed an NCT (Irish version of MOT) but he told me since he got it he was told by the previous owner the car looses water/coolant when driven hard but normal driving barely uses any and he's been driving it this long just wondering what it could be? Surely engine wouldn't last this long with a head gasket gone? Is it a common thing for these cars or what you guys think?