You pay the deductible when you use the coverages that are associated with your deductibles thus collision and comprehensive. It is not a yearly or annual payment but one paid out when you have an accident or loss and make a claim.
A deductible must pay on each loss to which the deductible applies. So if you have 2 or more accidents in a year for each incident that you use your own insurance coverages that have a deductible associated with it you would pay the deductible. So, no the deductible is not due only once a year or annually but is owed for each time you use a coverage that requires a deductible to be paid thus per claim.
The deductible needs to be paid when your coverages, usually comprehensive or collision, are covering a loss. So if you have multiple incidents in one year that has you placing multiple claims through your insurance policies you will need to pay multiple deducible amounts.
If you are in multiple accidents during the year and do not get the pre-existing damages repaired and you sustain new damages in the same area as the previous damages then you may have had your claim reduced by the cost of the pre-existing damages that you chose to not repair. That is one reason why it is important to repair damages to your vehicle so that future claims will not deduct pre-existing damage.
My wife had a minor accident a few months prior and we didn't get it fixed. Then, she had a major accident recently. When settling the claim and got the car fixed, we paid 2 deductibles because the damage fixed from the first accident required a deductible and the damage from second accident required a deductible. I hope this helps.
You can read through the terms of your auto insurance policy and speak with your insurance provider's agent to get more information on your deductible amounts and when they are due once you have placed a claim.