When handling collections of debts, what would make my job a lot easier is if the debt itself was evidenced by writing. This could be in the form of an invoice, purchase order, promissory note, personal guaranty or contract. However, any written memorandum signed by the debtor will work. I have sued on handwritten notes more than once and have always been successful in obtaining judgments thereon. I have also sued successfully on checks evidencing payment on a portion of the debt. Therefore, my advice to everyone is obtain written evidence of the debtIn addition, the writing should include as many terms as possible. For example, a contract, purchase order or invoice should include the specific terms of payment as well as provisions for interest. My clients often want me to include a claim for interest. Right now, the legal rate of interest in Florida is roughly 4.75% per annum which is rather low. By specifying the interest rate to be applied in writing, you may obtain interest up to 18% legally per annum in Florida.