(4) the division of responsibility among firms is reasonable in light of the client's need that the entire representation be completely and diligently completed.
Reasonableness of Fee and Expenses
 Paragraph (a) requires that lawyers charge fees that are reasonable under the circumstances. The factors specified in (1) through (8) are not exclusive. Nor will each factor be relevant in each instance. Paragraph (a) also requires that expenses for which the client will be charged must be reasonable. A lawyer may seek reimbursement for the cost of services performed in-house, such as copying, or for other expenses incurred in-house, such as telephone charges, either by charging a reasonable amount to which the client has agreed in advance or by charging an amount that reasonably reflects the cost incurred by the lawyer.
 When the lawyer has regularly represented a client, they ordinarily will have evolved an understanding concerning the basis or rate of the fee and the expenses for which the client will be responsible. When the scope of the representation changes, in a material way, the lawyer should notify the client about the changes in writing. In a new client-lawyer relationship, however, a written understanding as to fees and expenses must be promptly established. Generally, furnishing the client with a simple memorandum or copy of the lawyer's customary fee arrangements will suffice, provided that the writing states the general nature of the legal services to be provided, the basis, rate or total amount of the fee and whether and to what extent the client will be responsible for any costs, expenses or disbursements in the course of the representation. A written statement concerning the terms of the engagement reduces the possibility of misunderstanding.
 Contingent fees, like any other fees, are subject to the reasonableness standard of paragraph (a) of this Rule, including consideration of the degree of risk assumed by the lawyer at the outset of the representation. In determining whether a particular contingent fee is reasonable, or whether it is reasonable to charge any form of contingent fee, a lawyer must consider all of the factors that are relevant under the circumstances. Applicable law may impose limitations on contingent fees, such as a ceiling on the percentage allowable, or may require a lawyer to offer clients an alternative basis for the fee. Applicable law also may apply to situations other than a contingent fee, for example, government regulations regarding fees in certain tax matters.
 A lawyer may require advance payment of a fee, but is obliged to return any unearned portion. See ER 1.16(d). A lawyer may accept property in payment for services, such as an ownership interest in an enterprise, providing this does not involve acquisition of a proprietary interest in the cause of action or subject matter of the litigation contrary to ER 1.8(i)
. However, a fee paid in property instead of money may be subject to the requirements of ER 1.8(a)
because such fees often have the essential qualities of a business transaction with the client.
 An agreement may not be made whose terms might induce the lawyer improperly to curtail services for the client or perform them in a way contrary to the client's interest. For example, a lawyer should not enter into an agreement whereby services are to be provided only up to a stated amount when it is foreseeable that more extensive services probably will be required, unless the situation is adequately explained to the client. Otherwise, the client might have to bargain for further assistance in the midst of a proceeding or transaction. However, it is proper to define the extent of services in light of the client's ability to pay. A lawyer should not exploit a fee arrangement based primarily on hourly charges by using wasteful procedures. When there is doubt whether a contingent fee is consistent with the client's best interest, the lawyer should discuss with the client alternative bases for the fee and explain their implications.
Prohibited Contingent Fees
 Paragraph (d) prohibits a lawyer from charging a contingent fee in a domestic relations matter when payment is contingent upon the securing of a divorce or upon the amount of alimony or support or property settlement to be obtained. This provision does not preclude a contract for a contingent fee for legal representation in connection with the recovery of post-judgment balances due under support, alimony or other financial orders because such contracts do not implicate the same policy concerns.
Disclosure of Refund Rights for Certain Prepaid Fees
 Advance fee payments are of at least four types. The “true” or “classic” retainer is a fee paid in advance merely to insure the lawyer's availability to represent the client and to preclude the lawyer from taking adverse representation. What is often called a retainer but is in fact merely an advance fee deposit involves a security deposit to insure the payment of fees when they are subsequently earned, either on a flat fee or hourly fee basis. A flat fee is a fee of a set amount for performance of agreed work, which may or may not be paid in advance but is not deemed earned until the work is performed. A nonrefundable fee or an earned upon receipt fee is a flat fee paid in advance that is deemed earned upon payment regardless of the amount of future work performed. The agreement as to when a fee is earned affects whether it must be placed in the attorney's trust account, see ER 1.15, and may have significance under other laws such as tax and bankruptcy. But the reasonableness requirement and application of the factors in paragraph (a) may mean that a client is entitled to a refund of an advance fee payment even though it has been denominated “nonrefundable,” “earned upon receipt” or in similar terms that imply the client would never become entitled to a refund. So that a client is not misled by the use of such terms, paragraph (d)(3) requires certain minimum disclosures that must be included in the written fee agreement. This does not mean the client will always be entitled to a refund upon early termination of the representation (e.g., factor (a)(2) might justify the entire fee), nor does it determine how any refund should be calculated (e.g., hours worked times a reasonable hourly rate, quantum meruit, percentage of the work completed, etc.), but merely requires that the client be advised of the possibility of the entitlement to a refund based upon application of the factors set forth in paragraph (a). In order to be able to demonstrate the reasonableness of the fee in the event of early termination of the representation, it would be advisable for lawyers to maintain contemporaneous time records for all representations undertaken on any flat fee basis.
 The State Bar of Arizona has established an arbitration procedure for the resolution of fee disputes. Each lawyer should conscientiously consider submitting to it. Law may prescribe a procedure for determining a lawyer's fee, for example, in representation of an executor or administrator, a class or a person entitled to a reasonable fee as part of the measure of damages. The lawyer entitled to such a fee and a lawyer representing another party concerned with the fee should comply with the prescribed procedure.