Building toys change a lot as children grow, so start with their hands. Toddlers need big pieces that push together easily, like Mobilo or chunky blocks. From about five, smaller parts that click, screw or bolt together give them something to work at, and kits with instructions become fun rather than frustrating.

The sets we like best can be built more than one way. A kit that makes exactly one model gets finished and put on a shelf. A tub of pieces gets tipped out again next week.

If you're adding to a set they already own, check it's the same system. Mobilo, Plus-Plus and most construction brands don't fit each other.