1. Immediate needs. Think about what you need to get by right now. What are your financial needs? Safety needs? Transportation needs? Travel schedule? Kids' needs? You probably have monthly statements, letters, memos, notices, contracts and other records that relate to your immediate needs.
2. What are your end objectives? Consider what you want to end up with and gather any relevant information about that. For example: school costs, transportation needs, insurance, job training, retirement plans, debts to pay, housing, etc. Think about your long-term needs and wishes.
3. Get what you can. On a practical level, you may not have access to a great deal of information, so just grab and copy what you can. If you do have access to a substantial amount of information, go ahead and start copying it. You will likely need it at some time during the litigation process. Don't wait until later because things tend to disappear.
Income, expenses and debts. Gather pay stubs, W-2 forms, tax returns and the annual Social Security statement showing your earnings and projected retirement payments. You need to have a budget or two. Preparing a current budget (with everyone living together) would help and you will need a new budget for after separation.
Bank statements. Get as many as you can, for all accounts, for up to the last three years.
Credit card statements. Ditto. It's amazing what you can find on credit card records.
Kid information. If there are children and there may be disputes on custody and access/visitation, you should gather a variety of records. These include school records (attendance, grades, conduct), medical care, dental records, expenses and scheduling.
Web information. Please gather relevant website information that has access to financial, medical and school records, as well as social media sites such as Facebook, Instagram, YouTube, Google +, Twitter, and others. We need user names and passwords. That should be for both you and your spouse. If you or your spouse have websites or blogs, please provide that information as well.