Welcome @MichiganJules
It all depends on the circumstances and what was arranged when you confirmed the sit. Did you already agree an arrival time on the start date before the sit was confirmed?
You are not obliged to offer accommodation the night before the start date - ,however we have been offered this on sits when the owner is leaving first thing in the morning. It makes sense if your sitter is travelling a distance to travel to you , you have an early departure and you need them to be there to handover before you leave.
If the handover is going to be later in the day then there is no need for the sitter to stay over in your home the day before .Although some hosts may offer this .
As a rule of thumb the sitter arrives on the start date and not before.
Some hosts have build in an extra overlap day when listing their dates for their own peace of mind , if the sitter is arriving from a distance by public transport incase of flight delays etc
If it’s awkward to have someone stay over in your home , some hosts handover to the sitter and then go to a hotel themselves the night before their early morning flight.
If the sitter you have chosen doesn’t have a car it’s both hospitable and practical to offer to pick them up from the airport/ bus terminal. However that would usually be discussed before confirming the sit .
So there’s no right or wrong or usual , it will differ depending on the circumstances.
This has also been discussed previously on this thread