The main reason for people deciding to act in person is that they cannot afford the legal fees. Other reasons include:
In some jurisdictions the litigant in person is entitled to bring a friend into court to provide assistance. In the UK this person is known as a McKenzie Friend.
A special category of litigant in person arises when a defendant in a criminal case dismisses their defence counsel and chooses to defend the case themselves. This is almost invariably an inadvisable course of action, since the law and procedure can be complex and the penalties if convicted can be severe. Furthermore, in some jurisdictions the litigant in person is restricted from cross-examining the alleged victim in rape and other serious sexual offences. The underlying policy is that an alleged victim should not have to answer directly to an alleged rapist. The right of the individual to defend themselves is in conflict with the need to protect the alleged victim from any further humiliation. In the UK this conflict is resolved by the court appointing a special counsel at public expense to conduct cross-examination.