The answer varies according to the environment:
Technically, it take 4-6 hours if it's done in one session and all the pre-requisites and requirements are already in place.
However, that is rarely the case and a lot of the time unexpected delays can occur (ports not open, pre-requisites not installed, can't get an SA account etc.).
Therefore, a more accurate estimation would be 2-3 session each of 2-4 hours.
When working with SkypeShield credentials an internal Bastion is required and therefore the installation duration can get longer, it can require up to 2 more hours and will likely require another session.
A good way to avoid this would be to make sure that the user used for the installation can edit "Delegation" on computer objects in the AD.
Note that very large environments with multiple pools, Front Ends, Edge server or a requirement for HA can prolong the installation time.
Below is a summery of hours for basic installation:
Topic | Time frame estimation (hours) |
Preparing system requirements | 8 |
Initial installation and requirements verification | 2-4 (Depends on topology) |
Configuration finalization and additional installation (if required) | 4 |
Training and enrollment | 2 |
Further testing | 2 |
For dedicated credentials, add one more session of 2-4 hours.