The numbers you referred to, 250/500/100, are Liability limits - not deductible amounts.
It can be confusing learning to read limits for Bodily Injury Liability since there are 2 sets of numbers such as 250/500 and then the last number 100 is thrown in there for Property Damage Liability to come up with limits of 250/500/100. There are not deductible amounts; there in fact is not a deductible due when Liability coverage is used, but the maximum payout amounts (limits) you have chosen for your Liability coverage.
The first number is the maximum coverage for Bodily Injury Liability for one person injured in an accident (in thousands). The second number is the maximum coverage for Bodily Injury Liability for one accident/incident (in thousands). So the dual coverage limits refer to the maximum amounts that will be paid per person, per incident, respectively.
In basic language this 350/500 stands for $250,000 per person for bodily injuries sustained in one accident and topping out at a maximum payout of $500,000 for all claims against the Bodily Injury Liability coverage. So the 250 is for the maximum $250,000 per person coverage and the 500 is for the maximum $500,000 limit for all bodily injury claims from one incident or accident.
Bodily Injury Liability (BI) insurance is coverage for other people's injuries or death for which you are responsible. Bodily Injury Liability coverage can also provide legal defense if another party in the accident files a lawsuit against you. In general, you will want enough BI Liability insurance to cover a judgment against you in a lawsuit, so that your personal assets are not put at risk. It is advised that you should always buy the maximum amount of insurance that you can afford.
The first part of determining how much Bodily Injury Liability insurance you need is finding out your state's minimum limits. You will need Bodily Injury Liability limits of this amount and possibly more so that your house and personal items are not put in jeopardy if a lawsuit comes about due to a lawsuit. The amount you asked about of 250/500 is above the recommended amount of 100/300 so should be very good coverage for you.
Now the remaining 100 of the 250/500/100 limits you referred to is the limit for Property Damage Liability. This means with this coverage the insurance company's top limit they will pay out for the other person's property damage that you cause in your vehicle is $100,000.
Property Damage Liability covers you if your car damages someone else's property. Usually it is their car, but it could be a fence, a house or any other property damaged in an accident. It also provides you with legal defense if another party files a lawsuit against you. It is a good idea to purchase enough of this insurance to cover the amount of damage your car might do to another vehicle or object and with a limit of $100,000 you should be protected well.
As we mentioned Liability coverages do not come with a deductible. Your physical coverage damages of Collision and Comprehensive do come with a deductible that you choose when you set up your car insurance policy. A deductible is the dollar amount you must pay on each loss to which the deductible applies. The insurance company pays the remainder of each covered loss up to the policy limits.