Civil procedure
Every civil law claim may be subject of a lawsuit. Therefore it is impossible to exhaustively list all kind of lawsuits. For example lawsuits regarding ownership, personal rights, marriage, employment, damages, inheritance belong here as well as claims arisen from a payment obligation (e.g. purchase price, contractor’s fee, rental fee), invalidity of a contract or default performance thereof.
In some cases it is obligatory to have a legal representative in a court procedure but it is always highly recommended to hire an attorney-at-law as soon as possible, especially if the other party also has one. In most cases, a lawyer is needed in order to clarify the exact claims which could be successfully enforced before court in the given situation and to find the most effective defending arguments. Litigation must be well-prepared because in many cases it lasts for years and litigation costs have to be borne by the losing party. The later somebody hires an attorney-at-law, the less option remains.
Finally, it may be also necessary to involve an attorney-at-law in the law enforcement procedure following a lawsuit.
Furthermore, a payment claim may be enforced not only in a lawsuit but by way of an order for payment or liquidation procedure as well. All circumstances of the case need to be considered in order to choose the most adequate procedure. It is recommended to ask for legal advice in this question too.