Learn Finnish: Asiakkaalla on tapana hypistellä vaatteita. - The customer has a habit of fiddling with clothes.

The structure -lla on tapana literally translates to someone has [something] as a habit. The essive ending -na expresses a state, role, or condition. Even though English says 'has a habit', Finnish uses the essive to show the nature of the action rather than literal possession of a physical thing.

The verb hypistellä has a recognizable suffix. What does the -ellä ending do in this word?

It is a frequentative suffix. At B2, you will see this often: it changes a base action into a continuous, repeated, or aimless one. So instead of a single precise touch, hypistellä means repeatedly touching, fingering, or fiddling with something.

Why is vaatteita in the partitive plural here?

The verb hypistellä (to fiddle with) expresses an irresultative action, meaning it is an ongoing process with no final result or clear endpoint. This requires the object to be in the partitive case. Since it refers to clothes in general, it takes the partitive plural ending -ita.

Could I express this same habit using the verb tavata?

Yes, you could say Asiakas tapaa hypistellä vaatteita. The verb tavata can mean 'to tend to' or 'to have a habit of' alongside its common meaning 'to meet'. However, the on tapana construction used in this sentence is much more frequent and idiomatic for expressing personal habits.