Probably too many! This depends on where you plan to travel long distance, or where you need to regularly charge in public. Use a service like Zap-Map, A Better Route Planner, (ABRP) Google Maps, or in your electric vehicle's sat navigation to plan your journey and see what companies supply the charge.
Then sign up online to them. Some charing companies will send you an RFID card.
The good news is that many public charging facilities including Instavolt, Shell, BP and Ionity accept contactless payment, allowing you to turn-up and pay instantly with your bank card.
One aspect of contactless charging to note is that many companies deduct a pre-payment from your bank account before you can charge. After charging is complete then then credit back anything not spent on the prepayment. At the time of writing Shell UK takes a £30 pre-charge. Credits can take up to 30 days to reach your bank account, but are normally much quicker.