We will be arriving at Schiphol airport early on the morning of Sunday May 4. Three seniors, 2 of whom will most likely have checked luggage. I was thinking of a taxi to our hotel to drop off the luggage, rather than the train and then tram. Do I need to reserve one in advance? Or are there plenty of them at the airport? Thank you.
There should be taxis available outside the arrival hall: https://www.schiphol.nl/en/from-to-schiphol/taxi/. Do only take a taxi from the official taxi ring (just follow the signs and the yellow arrows on the floor), do not take any taxi offered to you in the arrival hall. Alternatively, you can order an Uber or Bolt upon arrival. There would be quite some time in the queue for passport control and while waiting for your suitcases to order an Uber.
You could also look at WelcomePickups.com - I've used them in a number of cities when arriving after an overnight flight when I'm tired. They will meet you in Arrivals, you'll have a driver who speaks some English, and they drop you at your hotel and often provide some commentary along the way. I like that I get a notice via their app in advance with the picture and license plate of the driver. If you give them your arrival info they monitor the flight and make adjustments if the flight is late. For example, for a recent trip to Palermo my flight was 2 hours late arriving and the driver was waiting for me when I got there, which is a big relief when I'm traveling solo. I've found their rates to be comparable to local taxi rates. Just a suggestion....
We used Welcome Pickups in Istanbul and we were pleased with the service.