Fruiting or non-fruiting lime trees

Fruiting or non-fruiting lime trees

I know (well, I've been told) that it is possible to have a non-fruiting LIME tree, so I'm wondering if anyone can tell me how many years of "growth" (without fruit) I should allow before I decide *my lime-tree is obviously never going to bear fruit* and pull it out of the ground to replace it. It's just that I see no point in watering and nurturing a tree (for now three years, and it's 5 foot tall) if it's never going to bear fruit. Thanks heaps :o)
Most curious

Most curious

Pond help!

Pond help!

Garden 2010

Garden 2010

Garden wildlife

Garden wildlife

Withered/ dried geraniums?

Withered/ dried geraniums?

Zucchini and/or sugar snaps in trouble?

Zucchini and/or sugar snaps in trouble?