Getting sued or about to sue someone else? There is an old saying from the New Testament that often applies: “For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.”
Put another way, build into your calculation of the value of settlement versus fighting the potential damage from a formerly-closeted skeleton putting on some of your dirty laundry and dancing around in front of a jury.
The rules of evidence are intended to keep unrelated matters from distracting judges and juries. But your opponent’s lawyer is likely to give some thought to how to apply those rules in a way that makes it more likely incriminating facts will be found relevant to what is admitted into evidence.
As well, what you get asked by the other side’s lawyer in a deposition is generally much broader than what eventually is admitted into evidence. Unless a question is being asked to harass you, the fact it is not directly on topic generally is not a valid reason for you refusing to answer it. (Depositions are one of the reasons lawyers aren’t often winners of popularity contests.)
Don’t let a few stupid mistakes you’ve made keep you from pursuing justice—chances are the other side has made some too. But neither should you assume you can guarantee your most serious errors from the past will remain hidden.
Above all, give your lawyer a heads-up about your skeletons—because the more often your lawyer is surprised by what the other side uncovers about you and your claims, the greater the chances you will be surprised by how badly you lose.