Best Practice for Timeliness?

Hey, I want to highlight rows in an index view based on their
timeliness. That is, is a record late, due soon, etc. Is it a better
practice to put the business logic in the helper or model?

While business logic should in fact go into the model
(if possible, otherwise controller, never in the view or helpers),
this isn't exactly business logic. It's just a question about
how to display some given data and that goes into
the helper or view.

that depends: generally spoken, business logic should be put into
models. but if you only want to change format, coloring, etc. thats a
typical helper-function.

Hey, I want to highlight rows in an index view based on their
timeliness. That is, is a record late, due soon, etc. Is it a better
practice to put the business logic in the helper or model?

Both. Add methods to your model such as is_late?, due_soon?, etc (returning true/false). Then in your helper method use those methods to determine what style to apply to the row.

-philip