I was driving in the middle of nowhere Montana and something from somewhere hit my windshield. The chip is about 75% of an index finger - so about a third of an inch.
Should this chip be filled in / repaired to prevent it from spreading? Or can it be driven as is?
While I agree with the comment from @GdD about this being subjective, I'll still answer this question to the best of my ability.
The chip itself (as it is right now) appears to be on the passenger side of the windshield. In most States, if the chip/crack interferes with your vision (ie: is anywhere on the driver's side of the windshield), the windshield will either need to be fixed or replaced.
As of what I see in the pictures, the chip can be fixed. It can be fixed to the point where if you aren't looking for where it was chipped, you'd never notice it was there. One of the things going on is it isn't exactly a bullseye chip, but rather is starting to web. If you don't get it fixed, you can be assured the cracks will spread. This is due to the fact you have stress risers in the glass now where the crack will continue to grow. If you get it fixed, it will keep the cracks from spreading. This will most likely save you from needing a new windshield down the road. Depending on the make/model/options of the vehicle involved, getting a new windshield is far more expensive than getting the chip fixed. As @GdD said in comments, your insurance company may pay for the chip repair, so cost should be minimal.
Since you said you were in Montana when this happened, I'll assume you are somewhere in the northern latitudes of the States where it continues to be cold this time of year. That said, the heat cycle of your vehicle (cold at night when it's shut off, warm when you're running it) will cause the windshield to flex, which will cause the cracks to grow. This may take some time, but it probably won't.
All this said, is it dangerous to run your vehicle like this? In most cases no. Because of how the windshield is designed (laminated layers), there's no fear of it falling into your lap while you're driving. There is always the fear of the cracks getting longer and getting in the way of your vision. This can limit your visibility and cause safety concerns. If you put off getting a chip fixed soonest, you will end up needing a windshield replacement which may not be cheap. My bottom line here is, fix the chip as soon as possible instead of waiting. It will save you a lot of issues down the road and will be cheaper in the long run, especially if the insurance company will pay for it.
