If you are using Google Analytics and are now tracking demographic information, start using the filtering feature to better understand your website's user experience based on their age. A 25 year old will have a different experience on a website than someone 60+ (in many cases), so by clumping all of that data together you aren't getting a true picture. In compiling these reports you may save yourself from jumping to conclusions that maybe aren't true.
What if you knew that your website was performing very well for the 45+ age group but poorly for the 25 and under? If you have a higher volume of 25 and under visitors, they'll have a greater affect on data slightly skewing your overall numbers. Would you want to change everything on your site to fix this? If you do you might be risk losing the high performing 45+ group. As long as you have enabled demographic targeting, you'll be able to look at this data on a more granular level and making better improvement decisions.
How to Create Google Analytics Age Filters
These are actually referred to as "Segments" in Google Analytics, but the way we'll be using them here, they will be acting more like filters, so we're just going to stick with that.
If you test the segment (filter) and it affects 0% of traffic, you've done something wrong or you don't have demographic tracking set up properly. If it did work it will take you to the filtered view of the data. By just looking at this filtered view you'll get an idea of how that segment performs wherever you go in Google Analytics as long as you don't remove it.
In this view I could compare performance on a tablet, desktop and mobile for only visitors that are 45+ (according to Google). By adding multiple filters I can get a side by side comparison of how visitors age 45+ compare to visitors less than 45 on each of these devices.
The filters that you set up will vary based on what is important to you. I'd recommend starting at the overall age view seen at the screenshot below. From here you can see an overview performance by age. Don't stop here as the overview view doesn't really allow you to see where improvements need to be made. By adding the filters you can view by device type, content, location, conversions, sales, etc. Digging into the data not only gives you a more detailed view of performance, but will make your improvement areas much more clear.
Remember, one of the great aspects of online marketing is the measurability/trackability. The data is there, use it!