A few financing questions

[Daniel Soovajian]

Hello!

I'm looking to get pre-approved for a conventional mortgage and wanted to start by comparing lenders based on the interest rates, points, fees, etc. they're offering. A few questions came to mind as I started to kick off this process and I'm hoping to lean on the expertise of the BP community for guidance on them: 

1) Do I need to go through the underwriting process and get pre-approved with each lender in order to see what rates, fees, etc. I would actually be charged on my loan? It seems like this would be the best way to compare lenders but I'm concerned about all the hard credit checks that would result from doing this kind of comparison shopping. Or could I call each lender and without going through the pre-approval process with each of them, have them give me a ballpark estimate for what those rates, fees, etc. would be - so that I could rule out some lenders and just move forward with getting pre-approved with a few of them?

2) I've read that you can minimize the hit to your credit score by getting all the pre-approvals done within a short period of time so that they are counted together. Depending on where I'm reading, I've seen folks suggest that I should have all the hard credit checks done within a 14/30/45 day window to take advantage of that. Can anyone confirm what the actual window is?

3) Once I have the pre-approvals in hand, I understand they're usually only good for a limited period of time (e.g. 60 days), but that I can supply updated information to the lender and they'll extend the shelf-life for my pre-approval for another few months. Are additional hard credit checks taking place to conduct this extension?