What is an Ad Set?

An ad set is the second level in the campaign structure of Meta Ads. At campaign level you set the objective; at ad set level you define the audience, the budget, the schedule and the placements; at ad level you choose the creative. An ad set combines one audience with one budget.

What do you set at ad set level?

The audience (custom audience or lookalike audience), the budget (daily budget or lifetime budget), the schedule (always on or at set times), the placements (Feed, Stories, Reels, Audience Network) and the optimisation for clicks, conversions or impressions.

Ad sets and testing

By running several ad sets with different audiences, you test which targeting performs best. This is the basis of A/B testing at audience level. Make sure every ad set has enough budget to get out of the learning phase.

Advantage+ ad sets

Meta has introduced Advantage+ campaigns in which targeting is largely automated. This can be effective when you have enough conversion data, but it gives less insight per segment than manual ad sets.

How many ads should an ad set contain?

Meta recommends three to five ads, so the system can identify and optimise the best variant.

What is the difference between a daily budget and a lifetime budget?

A daily budget allows Meta to spend up to that amount per day. A lifetime budget applies to the entire campaign period. More at developers.google.com/search.