There is no single answer that is valid for everyone since it depends on the time you have for your trip, and the desire you have to deepen the visit.
From our experience, we would tell you that what more satisfies most travelers is spending three whole days visiting temples of Angkor, since 3 days is enough time to see the most interesting, and at the same time if you make a good selection the temples are very varied, and even travelers who tire quickly of the stones do not have time to get bored.
Despite this, those who only have one day also have enough time to visit the main temples (in this case we recommend focusing the visit on Angkor Wat, Angkor Thom, and Ta Prohm temple), and whoever has enough time and predisposition to visit the place give to dedicate all the days you want.
Can overcrowding be avoided?
The temples of Angkor receive more visitors every year, and as you can imagine, nobody wants to miss the most famous temples (Angkor Wat, Bayon, Ta Prohm, Banteay Srei), which everyone goes to.
Due to a large number of tourists, we advise you to follow certain strategies to avoid overcrowding as much as possible.
Related post: A Guide to Visit Angkor Grand Circuit Temples
On the one hand, you have to know that the high season is between November to February (which is when the weather is dry and the coolest it can be in Cambodia), and at this time there is more tourism than in May and October (low season), although then it is warmer and it is the rainy season.
The quietest time of the day is during lunch time, as many of the large tour groups return to Siem Reap to eat.
It has the disadvantage that it is the hottest and sunniest time of the day, but in the cool season it is a good option to take advantage of this strip to visit the most famous temples, and even in the hot season it can be used to visit the temples with forest cover, like the Ta Prohm or the Preah Khan, or to admire the magnificent bas-reliefs of Angkor Wat.
You can also read our previous article: When is the best time to visit Cambodia?