I get a lot of these questions, should I use 1 day or 7 day click? There are many factors to consider! In order for Facebook to do it’s work to get you conversions, you will need at least 25 – 50 conversions tracked per week.
Facebook will only optimize your conversions based on the data from 1 day window. This is for high budget adsets, take in mind that you need 25-50 conversion per week. If you are using 1-day Click you should be at least be getting 25-50 conversions per day. If you do not have that much conversions per day it would be hard for facebook to use the data from the day before which is why you would use 7-day click. The 7-day click will have a bigger data window if your not getting 25-50 conversions a day.
This means that Facebook will optimize your conversions based on the data you gain in the last 7 days. I would use this for small budgets. Remember that you will need 25-50 conversion per week for Facebook to be fully working. Since you are not getting 25-50 conversion per day you should not use 1 day click but instead use 7 day click. If you have a small budget I doubt you are getting 25-50 conversions a day, if you use 1 day click it would not have enough data to be optimized. 7 Day click would be best for less than 25-50 conversions a day.
In conclusion, you would use the click window based on how many conversions you are getting per day. Remember that you will have to test these methods, some may work, some may not. At the end you will need at least 25-50 conversions tracked per week for Facebook to be fully optimized. You would use 1-day click if you are getting that 25-50 conversions a day. You would use 7-day click if you are not getting 25-50 conversions a day.