The answer always depends on the local situation (not described), type of clients (not described), their behavior (not described), expected functionality - mainly throughput (not described) and other restrictions (not described).
OK, fair point.
It's a residential block of 8 units, 4 on each side, with a eating hall in the middle (9 main buildings), length is 175 feet, width is 65 feet, or 100 feet if you include the hall.
Being a residential block, clients will range from PC's to smart TV's, Xbox's, tablets & other mobile devices & the odd IoT device.
behavior will include total bandwidth of about 1.5TB a month, (total) speed will only need to be about 20Mb/s, mostly accessing consumer url's. Maybe the occasional VPN.
restrictions (since you asked), some blacklisted IP's, individual client bandwidth limited to 10Mb/s, hopefully some traffic shaping rules in place.
That's a general sketch, nothing too elaborate. My question specifically is how would I approximate how many AP's to install. Mentally, I'm thinking either 2, to cover the width, or 4 or 5 to cover each main portion of the building. 5 seems like overkill, but better than having dead spots... Thoughts?