How long do I have to wait?
Stress 'as-pet-TA-re'. Simple, direct question.
Ask this when you arrive at the salon and are not sure how long before your stylist is available, especially if you're on a tight schedule.
'Quanto devo aspettare' = how long must I wait. 'Devo' = I must/have to (from 'dovere'). 'Aspettare' = to wait. Very simple and direct — suitable for all contexts. 'Quanto tempo' can be added: 'Quanto tempo devo aspettare?'
C'è molto da aspettare?
Is there long to wait?
Vaguer version.
Sono in anticipo. Posso aspettare qui?
I'm early. Can I wait here?
When you've arrived early.
Ho fretta. È possibile prima di me?
I'm in a hurry. Is it possible to go before?
Requesting priority.
Italian salons almost always offer waiting clients a 'caffè' (espresso) or 'un po' d'acqua' (some water). This hospitality gesture ('accoglienza') is standard and part of the Italian service culture. Refusing politely with 'No grazie, va bene così' is perfectly acceptable.