A column becomes more impressive when 8.2 changes to 8.2000. Nothing new has necessarily been measured. The spreadsheet may simply be showing extra zeros. Before comparing very small differences, ask how the values entered the table in the first place.
Keep the recorded value beside its method
Imagine a classroom exercise in which a reader records a length as 8.2 cm. Formatting that entry to four decimal places does not establish the length to a ten-thousandth of a centimetre. A useful record would also describe the measuring tool, procedure and recording convention.
Do not invent those details after receiving the file. If the method is absent, mark it as missing and ask the data provider. The tidy appearance of a column cannot answer a question about how the observations were made.
Resolution is about distinguishing changes
The NIST measurement handbook describes resolution in terms of a measurement system’s ability to detect and faithfully indicate small changes. It explicitly cautions that displayed digit count does not by itself establish an instrument’s resolution.
This also means that a screen with many digits is not enough evidence for a claim about tiny differences. Instrument specifications and the actual measurement conditions deserve attention. Formatting is one part of a data workflow, not a replacement for that information.
Make the uncertainty visible in the question
Suppose two illustrative rows contain 8.20 and 8.21. You can calculate a numerical difference, but whether the measurement system meaningfully distinguishes those values remains a separate question. Write both parts down: the arithmetic result and the information still needed to interpret it.
When preparing a chart, use labels that suit the documented measurements rather than adding decimal places for visual consistency alone. Keep an unchanged copy of the received data and record display choices. Our note on rounding during calculations addresses another stage of the workflow; rounding arithmetic and establishing measurement detail should not be confused.