To ensure your model meets thickness guidelines, you can use Netfabb's Analysis tool to flag sections below a certain thickness. You can also use Netfabb's Measuring tools to manually measure specific areas of your model.
1) Open your model in Netfabb and click on it so that it is highlighted:
2) Hover over the "New Analysis" icon on the toolbar at the top of Netfabb and select "Wall Thickness"
3) On the "Wall Thickness" dialogue that appears, set your threshold (based on the Design Guidelines for the material you're looking to print in) and click "OK"
4) Any sections below the threshold you set, will be highlighted red:
Checking Wall Thickness Manually
1) To manually check a specific section's wall thickness, click on the "New Measurement" tool icon:
6) Select the Wall Thickness icon on the right-hand side:
7) Click on a section of your model and a measurement of its thickness will be displayed:
Fixing thickness issues
You can use the Extrude Surfaces option within Netfabb to address any thickness issues you come across. A tutorial for this process can be found here: To Extrude Surfaces.