How long before you change targeting
Many people are curious about how long it takes to change targeting, precisely how long before they should change targeting when they've done some keyword research and found opportunities. The answer is that you don't have to wait! You can start researching and changing your keywords right away!
It's a good idea to keep the exact targeting for the campaign's duration, but if you're worried about how long you should keep it the same, give it a month. If you change it early, you're missing out on potential customers who might have been interested in your product. If you're still getting clicks on your ad a month later, you can test out different targeting options to see which ones will work best.