In the labyrinth of financial planning, particularly for retirement, the concept of engaging a Fee-Only Retirement Planner (FORP) has become an increasingly popular approach. This shift can be attributed to the transparency and objectivity of this model, as the planner’s compensation is directly from the client and not influenced by commissions or referral fees. Yet, it is also prudent to understand that hiring a FORP calls for a structured financial budgeting exercise.

One of the fundamental tenets of economic theory is the principle of scarcity - an individual has unlimited wants, but limited resources to reach those wants. This principle is applicable when considering hiring a FORP, as one needs to balance the desire for expert guidance against the cost of the service. Thus, a budgeting perspective becomes indispensable.

The first step in this budgeting odyssey is to understand the cost structure of FORPs. Typically, these financial advisors charge a percentage of the assets they manage, a flat fee, or an hourly rate. The amount varies based on the complexity of the individual's financial situation, the level of assets under management, and the experience of the planner.

The subsequent step involves a thorough audit of your current financial status. This includes an assessment of your income, expenses, assets, and liabilities. Additionally, it is critical to earmark funds for emergency situations – a concept drawn from the modern portfolio theory, which advocates for diversification to manage risk.

The next phase involves setting clear financial objectives. This could range from saving a particular amount for retirement, achieving a certain standard of living post-retirement, or even specific goals like purchasing a second home. With these goals in hand, one can ascertain the level of assistance needed from the FORP.

With the foundation set, one can now move towards the construction of the budget. This begins with the allocation of funds from your income towards the FORP's fee. This allocation should be considered an investment towards achieving your retirement goals, rather than an expense.

The implementation of a budget is another quintessential aspect. There are numerous budgeting techniques available, such as the envelope system, zero-based budgeting, or the 50/30/20 rule. Each technique has its pros and cons, and the choice depends on one’s personal preference and financial discipline.

The final step in the process is monitoring and adjusting the budget as per changes in financial circumstances or retirement goals. It is imperative to remember that a budget is not a static document, but a dynamic one that needs to be reviewed periodically. This is akin to the Black-Scholes Model in options pricing, where continuous adjustments are needed due to changes in underlying factors.

In conclusion, engaging a FORP can be a game-changer in achieving one’s retirement goals. However, it is paramount to create a robust budget to manage the costs associated with this service. After all, as the famous aphorism of Benjamin Franklin goes, "Failing to plan is planning to fail." Through careful budget construction, regular monitoring, and smart adjustments, you can ensure that the cost of engaging a FORP becomes an investment that bears fruit in the form of a comfortable and secure retirement.