The answer to 'why is my paver bare spots' is that there are a few common causes, including improper installation, settling, and weed growth. Bare spots on pavers can occur when the base material shifts or compacts over time, leaving gaps. Weeds can also grow up through the spaces between pavers, creating unsightly bare patches. To address this issue, you'll need to inspect the area and determine the root cause.
If the problem is due to improper installation, such as an inadequate base or gaps between pavers, you may need to have the area re-laid by a professional landscaper. This will ensure the pavers are properly supported and secured. If the issue is weed growth, you can try manually removing the weeds and applying a paver joint sand or sealant to fill the gaps and prevent future weed growth.