There are advantages of manual editing of mesh like being able to apply mesh controls in areas of interest or intricate areas. The thing with any FEA program is that the finer the mesh and the more elements/nodes you create the longer the solve time. Finer mesh does not always mean better results. I have run studies where refining the mesh more does not yield much different results. There are many options for mesh settings and mesh controls. There are also adaptive mesh methods that are worth looking into. You may check into h-addaptive and p-adaptive methods in the help docuemntation. Meshing is a topic you can go on for a while. There are limitations you dont want to get too crazy with refining the mesh because it can hog up all of your memory. Also when you are analyzing thin parts you want to make sure that you have enough elements going through the thickness of the part. I would recomend taking the SolidWorks Simulation course from your reller. I teach this course and it goes into detail about the different ypes of elements, mesh controld, adavptive meshes, the effects that changing mesh size and order has on the results.and so on.