The first decision to be made when filing a case is deciding which chapter to file. For most individuals it will be a chapter 7 or chapter 13 case. There are requirements to be eligible for each chapter. Your income must fall under a certain threshold to be eligible for chapter 7. Your debt totals must fall under another threshold to be eligible for chapter 13. If you income is too high for chapter 7 but your debt totals are too high for a chapter 13, you may be one of the few who need to file an individual chapter 11 case. Others might need to file a chapter 7 followed immediately by a chapter 13 to accomplish their goals. If you're filing bankruptcy without an attorney, you need to be able to evaluate your eligibility for each chapter and decide if that chapter will accomplish your goals.
In a chapter 7 case, once you file, you cannot just dismiss your case which means some mistakes are set in stone once you file. For instance, if you file with an asset you thought was exempt, but it turns out that asset is not exempt, there is not much that can be done at that point. You'll likely lose the asset.
It's also possible to make expensive mistakes in a chapter 13 case. Each chapter 13 case includes a calculation of the debtor's "current monthly income" and in some cases a separate calculation of "disposable income." These calculations are incredibly complex with hundreds of potential variables. To do the calculations properly, you might need to know whether a child in college, not living at home, can be included in your "household size" or whether you deduct your actual car payment expense or the IRS's standard car payment expense.
Many bankruptcy attorneys offer free initial consultations to discuss which chapter would be best and how much it will cost. You may also be able to make payments to pay for the bankruptcy. The cost of all the potential mistakes that can be made filing bankruptcy without a lawyer are greater than the cost of hiring an attorney.