Due to the nature of photography, not everything you capture through the camera can be in focus. It's a bit similar to how our eyes work, either something in the foreground or background is in focus.
As a Product Photographer, you can't afford to lose any detail when taking pictures of commercial products. Often photographers may love to use the bokeh effect but this should only be used for creative effect. If you're taking a photo of a product and something is out of focus, you would definitely be questioned as to why that was.
One way to get everything in to focus is to take photos at f/22, however you're then met with lighting and grain issues. This is where focus stacking comes into it. It's not a foolproof solution by all means but it will save you a lot of time. Focus Stacking as the name suggests, is literally taking a set of photos and placing (or stacking) each one on top of the other. The only difference between the photos are the focus points. Starting at one point in the set up slowly making your way back, each time only moving the focus ring on the lens. The more photos you take, the more accurate the end result will be but beware of the massive file sizes especially if you're working on RAW.
There are specific software for Focus stacking, but you just can do it quite easily in Photoshop too. Click here to watch a quick video by 'PHLEARN' on how you can achieve Focus Stacking in Photoshop.