Can I sue my clients if they refuse to paya after I am done working for them?

[Btaliat]

One of the beauties of freelancing services is that you can sue your clients if they don't fulfill the part of the contract. Before a client will sue his clients, there is a need to ensure that you have concrete evidence that will let you prove your points against such clients. To make it easier as well, make sure that you allow the legal experts to interpret some terms for you. What do you think about this?