You are obliged to leave the hotel at 10am, you have big bags and inevitably your next transport is only planned late in the evening... So you will probably be, like us, looking for a place to leave them for the day and enjoy the big apple until the last moment.
First thing to do: check with your hotel / hostel to find out if it has its own storage room. It is common, practical and very often free. Being in Airbnb, we didn't have this option so we went looking for a "safe" place to get rid of our burdens (we have 2 bags per person which makes us 20 and 25 Kg to carry). Second thing to do: if your starting point does not provide instructions, in our case it was Penn Station, find one not too far away. There are services for luggage drop, visit www.nannybag.com/ for more about luggage storage in New York.
We have selected for you 2 addresses that we visited the day before the departure and we have made our choice. We will explain why, our impressions and give you all the details (price / location / reception / type of storage).