Short answer: Check the batch and year, completeness of chapters, amount of marking and whether the content matches your syllabus.
Batch and year
Ask which batch and year the modules are from.
Completeness
Confirm every chapter and sheet is present.
Marking
Look at photos for heavy marking.
Browse second hand books.
Frequently asked questions
Why does the year matter?
Syllabi and patterns change.
Can I chat with the seller?
Yes, through in-site chat.