Will two packs of certo last longer?

Yes, two packs of Certo will generally last longer than one pack, assuming you use them in the same recipes or applications. The shelf life of Certo, which is a brand of pectin used for canning and making jams and jellies, is typically stable for a long time if stored properly. However, it's important to note that the effectiveness may diminish once opened, so it's best to use them within a reasonable time frame after opening.