I think feet and inches will be around for a long time yet! As someone who works in the building industry I can vouch for the fact that feet and inches are still used on site and with abandon... you can see why: " I need 20 8'x4' sheets of 3/4" WBP and 30 4x 11/2" 16' lenghts for tomorrow" is instantly familiar to all on the site, translate that into metric and it becomes: "I need 20 2.4x 1.2m sheets of 19mm ply and 30 100mm x 38mm 4.8m lengths.." A bit of a mouthful. Metric is always used on building plans but when ordering materials (particularly timber, concrete blocks and sheet materials) imperial figures are quite often substituted, or used in conjenction with their metric counterparts. A lot of the timber that comes into this country comes from North america where imperial dimensions rule so invariably this timber is graded and sold by the foot, inch and cubic foot. Most people on a site are familiar with both but when setting out or marking up work will generally be using metric as the drawings they work from are in metric.