What if a campaign is not spending all of the budget?

It's possible the impression share loss due to rank includes losing out on impressions that the campaign is eligible for but are very broad so you would not want to show for them anyway.

How often do we meet to review the campaigns?

You will receive a full report each month on your campaigns’ performance.

When is the best time to run Facebook Ads?

Wait a month or two (because you need to have good enough performance from one platform before testing new networks because it’s always an investment to start a new network and therefore a new learning period) and then launch a Facebook remarketing campaign.