Maintaining credibility during your contested divorce case is so important. When there are no documents on an issue, the judge will likely make a decision based upon who is believable or which person's statements make the most sense.
When the issues are financial regarding income, assets, debts, the source of those items, whether they were acquired before marriage or during the marriage often judges will make decisions (when there is no other clear proof) in favor of the person that they think tells the truth or does not exaggerate. Child support calculations, spousal support and equitable distribution are all affected by these determinations.
Clients who significantly under report their income, fail to disclose all of their assets, and claim that monies "disappeared" will have a much harder time convincing the judge that other financial claims that they make are valid. Of course when there are bank statements, tax returns, W-2s, title documents it is relatively easy to prove the value. However, sometimes those documents are not available due to age or absence and then the court has to determine if there is enough "credible" information to make a decision. A person who significantly misstates or denies assets that are on statements is going be viewed by the court with skepticism when they try to convince the judge of their financial claims.
A parent who is habitually late returning the children to the other parent or who always has an excuse why the parenting time could not take place, or why the children are not made available on time for pick-up, or who frequently bad mouths the other parent will lose credibility with the court. While there can be legitimate reasons why there are problems, once the court begins to believe that one person is the the creator of the problems or always making excuses the scales will begin to tip to favor the other parent who is seen as the victim of the false or misleading statements.
There is a legal expression that if you lie about little things you probably also lie about big things. Once a client loses credibility with the judge it can be very hard to restore. Judges use their common sense as well as training to decide issues. This is no different than what we do everyday with friends, family, acquaintances and business colleagues. If we know that we never get a straight answer from someone we tend not to believe many things that they say because of their reputation.