If you are going for something such as an In-wall aquarium, this will require quite a lot of installation work and you will need to schedule this accordingly. Always be open with your supplier as they will know the process inside out, and be able to advise you accordingly. For free standing tanks and table tanks then you will not need to worry so much, just allow your-self the time to get everything settled and start setting up the tank with your decorations/plants etc.