Bottom line: it depends.
Generally speaking, vehicle cell signal boosters can be installed faster than indoor boosters. Installation of the weBoost Drive 4G-S might take between 5 and 10 minutes, and the Drive 4G-M or Drive 4G-X slightly longer.
A simple installation of the Home 4G indoor booster might require 10 – 15 minutes, and for the Connect 4G you would need to allow more time. Obviously if the building requires a more complex installation, like multiple device-side antennas or pulling coax cable through an attic or crawl space, the job may take 2 or 3 hours.