Magnitude of magnification – Over-the-counter “readers” typically come in full-diopter steps (e.g., +1.00, +1.25, +1.50 … +4.00). 

• Make sure the strength matches your near-vision need so you don’t end up with eyestrain or headaches. 

Frame shape & fit – A square frame (as you mentioned) is stylish and often suits many face-shapes, but you’ll still want to check size, bridge width, temple length, and overall fit

Frame & lens material / quality – Good frames use durable materials (flex hinges, spring hinges, quality plastics/metals) and lenses may have coatings (anti-scratch, anti-reflective) or features (blue light filter).

Brand / return / warranty – For bundles especially, check the return policy, how consistent the lenses are, whether all frames function well, etc.

Bulk pack considerations – With an 8-pack you might accept slightly lower price, but you still want acceptable clarity and fit. Don’t assume cheap = ok without checking reviews