Your PLA or Product Listing Ad should use AdWords labels to help segment your data. There are several benefits of using Google AdWords labels to improve your PLA campaign.
You should certainly include AdWords labels for your campaign to ensure efficient testing so as to collect data on ad groups that are running as well as on bid amounts too. You just need to tick the check box that mentions the Ad Group or campaign next to your campaign name to activate AdWords labels. You can create a new label or just select an existing one.
You can also use AdWords label to log all changes and comparisons in your campaigns. While there are external applications such as Evernote to do the same, you can just use AdWords labels to view such changes with ease. Furthermore, you can also track any changes related to your AdWords login by using AdWords labels. You need to click on the Dimensions Tab and choose the View Labels option to view any changes made to ad groups along with the date on which you had made those changes.
You can also use AdWords labels to learn when those changes took place as well as compare the results before and after those changes were made for better monitoring.
Using AdWords labels is indeed an excellent and easy option to improve your PLA campaign and you should explore the above features to reap the benefits.