Screen size becomes a meaningful buying criterion when you connect it to a particular document. A short novel chapter and a scanned technical page do not ask the same thing of a tablet. Bring representative material to the comparison instead of judging only a colourful demonstration screen.
Open a page that usually makes you zoom, pan or turn the device. Try the orientation and application view you would use at home. Note how much of the page remains visible at the text size you find usable. The answer can be more informative than comparing diagonal measurements alone.
Distinguish reflowing text from a fixed page
Check the reading application's options for the actual file. If it can rearrange text to fit the display, a smaller tablet may still show a comfortable reading layout. If the document preserves a fixed page with diagrams, tables or annotations, the useful visible area can matter more.
Do not use a simplified demonstration document to settle a purchase for complex files. A two-column PDF, a wide table and a page with small figure labels expose different limitations. Include the type that occupies most of your reading time, then check an occasional difficult example too.
Try the larger device away from the display table
Consider its weight with the case you expect to use. A tablet resting on a store stand does not show what a long handheld session will feel like. If possible, hold the candidate in an ordinary reading position and check whether you can change pages without shifting your grip awkwardly.
Measure the bag compartment and the table space involved in travel. A larger screen can reduce document navigation while making the device less convenient to carry. That trade-off may be worthwhile for daily technical reading and less useful for a small amount of occasional reference material.
You can also separate locations: use a smaller tablet for portable reading and a computer display for large documents already read at a desk. This is worth considering before replacing a device solely for a task that rarely happens away from home.
After testing, write the reason for your choice in concrete terms. “The diagram labels remain readable with the whole page visible” describes a benefit. “The larger model looks more capable” does not tell you whether the extra size will improve the reading you actually do.
