The common scenario, (Openreach flavour) is where FTTP is available to order, once placed, records dictate whether a rod and rope task is required, this if needed will ascertain if new ductwork is required, or blockages need clearing.
The fibre install teams have been busy during lockdown, on some estates where lead in ducts exist, roping prior to any order ... meaning the task can be completed in one visit on the day of install.
There is such a wide variety of scenarios that a ‘one size fits all’ statement seems almost pointless.
If you can order, and you wish service, then go ahead place your order and let Openreach sort the rest out.