The Workrobot-Improvement-Unit gets really important to expand or rearrange rooms in shorter time. The needed time for expanding rooms and new constructions-sides increases rapidly! So have a close look to the time needed, else your working-bot can be occupied for days or weeks!
And you can put some rooms faster into storage and use other rooms for a time. For example, when you own a set of modifications-parts from workshop, you can put this room into storage for a while, to collect more ressources or build more attack-bots