Even if you’re only just considering buying your first EV or hybrid there are already familys out there with multiple EVs so it may not be that far off that you ask the question “Do I need two chargers?”
There’s no absolute answer but you shouldn’t worry about getting two chargers installed just because you think you might buy a second EV for domestic use. There are domestic chargers out there which can be daisy-chained or even come with two charging cables or sockets but there are trade-offs to consider.
In the commercial EV market it is not unusual to see dual-output chargers, in fact there are some chargepoints which offer triple- or quad-output, but these are always powered by a higher capacity electrical feed. Many offices and workplaces operate from three-phase 400v electrics which can easily be utilised to power multiple chargepoints of 7kW or more.
In a domestic or residential building you will almost certainly be limited to a single phase 240v supply. On a 32amp circuit (eg connect the charger to its own fuse in the main consumer unit) the most you will get is 7kW. So daisy-chaining chargers or fitting a dual output EV charger to this will just limit the charge to 3.6kW per car, therefore doubling the time taken to charge a vehicle.
Even if you installed two separate EV chargers on separate 32amp circuits you might not achieve the full 7kW output per charger as the supply to each will be load-balanced with whatever else is drawing power in the house.
The easiest option is to just organise the charging times between cars and take turns. Even an EV with a modest 100 mile range could cope with charging every couple of days when the average daily commute is only 25 miles and the average individual journey is 8 miles.
So just charge one car one day and the other car the next.