(a) A lawyer shall not enter into an agreement for, charge, or collect an illegal or unreasonable fee or an unreasonable amount for expenses. The factors to be considered in determining the reasonableness of a fee or expenses include the following:
(1) the time and labor required, the novelty and difficulty of the questions involved, and the skill requisite to perform the legal service properly;
(2) the likelihood, if apparent to the client, that the acceptance of the particular employment will preclude other employment by the lawyer;
(3) the fee customarily charged in the locality for similar legal services;
(4) the amount involved and the results obtained;
(5) the time limitations imposed by the client or by the circumstance