It depends on your campaign goals and budget flexibility.
Daily Spend: This is ideal if you have a fixed budget and want to control your spending daily. It ensures your ads consistently run within a daily limit but may restrict performance optimization over time.
Lifetime Spend: This is better for campaigns where you want to give Meta more flexibility to optimize ad delivery based on performance. Lifetime spending allows Meta's algorithm to distribute the budget more efficiently over the campaign duration, improving overall performance.
In general, lifetime spending is often recommended for campaigns focused on long-term goals, as it provides more room for the system to optimize. Daily spending suits campaigns with more immediate or fixed budget constraints.