Should expresses what may reasonably be expected to happen. It also carries the meaning that we want whatever is predicted to happen, and is therefore not used to express negative or unpleasant ideas. It suggests a conditional.
1.Our guests should be here soon(if they haven't got lost).
2.This homework shouldn't take you too long(if you've understood what you have to do).
3.We should be moving into our new house soon(as long as all the arrangements go smoothly).