Hi Swat,
Bummer nobody got back to you. :(
I work in property and casualty insurance in Colorado, and might be able to offer some advice. As far as car insurance goes, you don't really need to tie these values to what you do for a living. Bad accidents can happen to anyone, and they can be really bad no matter if you're unemployed, a doctor, a mom, a pastor.. you get the idea. You should tie these values to your skill as a driver, as well as your personal level of risk aversion. If you are thinking about an umbrella, consider your net worth, the worth of leveraged assets (like real estate, vehicles, etc), your yearly income, and your level of risk aversion. Remember that the advice I've given here is GENERAL, and you always, always, always want to read your policy from your carrier to know for sure exactly what they do and don't cover, so you know what you are and aren't paying for.
Bodily injury covers the driver and passengers in the other car in the case you are the at-fault driver in the accident. If you rear-end someone, and they didn't have their seatbelt on, fly through the windshield and land on their head in a busy intersection.. That's where BI kicks in. If your BI limit is $100,000 per person, and the injured party needs $250,000 in medical care, you're on the hook for $150,000. If I were writing your auto policy, I would not recommend going below $100k per person/$300k per accident on this. Remember that you never know how badly someone else might get hurt, or how many people/cars might be involved in an accident.
Property damage covers the other person's car in the case you are the at-fault driver in the accident. If you t-bone someone's 2018 Tesla Model S(uper expensive car), and it costs $100,000 to fix/replace it, but you only have $25,000 in property damage coverage, you're on the hook for $75,000. I wouldn't recommend going below $50,000 on this - most people's cars don't cost this much to fix or replace, but a lot still do.
Personal injury protection is sometimes referred to as medical payments coverage. This typically covers the passengers and driver in your vehicle, regardless of fault. This is good for covering your health insurance deductible/out of pocket maximum. $5000 will usually do it, but if you have a HDHP or high out of pocket maximum, you may want to go to $10,000 or $15,000. Likewise, if you're driving around clients, friends or children, it's good to consider raising this above the minimum. You may have good health insurance, but you never know what someone else's situation is.
Uninsured and Underinsured Motorist protection kicks in when the other driver's bodily injury limits weren't high enough. For example, if you get in an accident with another driver where they were at fault, and they have NO insurance, your UMUI will cover your bodily injury. Alternatively, if you get in an accident with another driver where they were at fault, but they only had BI coverage of $25,000 per person, but the cost to you was closer to $100,000, your UMUI coverage will kick in to cover the difference. This should match whatever your choice is for BI limits.
Collision covers damage to your car during an accident regardless of fault - although if the other driver is at fault, claim the damage on the property damage portion of their insurance before the collision part of yours. Comprehensive covers non-accident moments, such as backing into a pole, hitting a deer, car theft, broken windows, etc. These things really depend on the value of your car, and how much of that asset value needs insuring. If your vehicle is only worth $2000 (like mine), it doesn't really make sense to even have collision or comprehensive coverage with the lowest deductible. We just keep a few thousand handy in case it's new car time. If your car is worth $50,000, maybe it does make sense. If your car is worth $50,000, and you're comfortable shelling out another $50,000 for a whole new car in the event yours is stolen, then don't get the coverage. Here is where you decide how much financial liability you can handle, and how much financial liability you want to offload to your insurance carrier. You can get good car insurance prices with Collision and Comprehensive coverage if you choose a high deductible.
Car rental typically covers a daily reimbursement for car rental costs in the event your vehicle isn't road worthy or available after an accident/incident. Some places limit the amount per day, some places limit the number of days you can get reimbursed, and some places limit both. Usually, the cost of this coverage is not very high.
Roadside assistance - similar to above, usually the cost of this coverage is not very high.
Umbrella coverage kicks in in the event that damages are higher than the underlying limits on your insurance. For example, if you have 100/300 BI on your vehicle, but a 1 million dollar umbrella, your umbrella will kick in if the bodily injury to the other driver goes over $100,000, and will pay out up to 1 million dollars. Having an umbrella with a company usually requires you to have all of your policies with that company, and usually requires you maintain moderate to high liability limits on those policies. Agents/carriers are happy to write this since it guarantees your other business, it guarantees your other business will be priced higher, and is a pretty low maintenance policy. So, it's really up to you to decide if you need this or not.
And, if you give an agent an Umbrella policy, they're going to ask you about your life insurance... Be careful. :)
In any case, while you are shopping, get written quotes that break down the costs by line item, so you can see exactly how your premium is broken down.
I hope this essay helps!
Kayla