Between a savings account that pays little, a retirement savings plan whose tax treatment on withdrawal remains unclear to many, and everyday expenses that absorb almost all of a modest income, optimizing your personal finances starts with measuring the gaps. How much is actually left at the end of the month at different income levels, and where does that money end up?
Savings capacity by income: the real differences
An Insee study published in November 2024 confirms a finding rarely quantified in mainstream budgeting guides: wealthier households save a significant share of their income, while the most modest households save nothing at all. Applying the same allocation rule to every household is therefore out of touch with reality.
| Income profile | Observed savings capacity | Suitability of the 50/30/20 rule |
|---|---|---|
| Low-income households | None or negative (expenses exceed income) | Not applicable as it stands |
| Middle-income households | Low to moderate | Applicable with adjustments (lower savings share) |
| High-income households | Significant share of income | Applicable, or even exceeded |
Based on Insee data, this table shows that budgetary flexibility depends first and foremost on disposable income, not on the method chosen. A household whose fixed costs exceed half its resources does not need a better spreadsheet, but rather to reassess its unavoidable expenses.
The budgeting tools available on s-finance.fr can help identify these expenses and model different adjustment scenarios, taking the household’s actual circumstances into account rather than relying on a theoretical template.
Budget and expenses: what fixed costs conceal
Most personal finance guides distinguish between fixed and variable expenses, then recommend cutting the latter. This approach overlooks a more effective lever: renegotiating fixed costs themselves.
Insurance, energy, telecoms: three costs you can renegotiate
A home or car insurance policy taken out several years ago often costs more than an equivalent plan available today. The right to cancel at any time, introduced by the Hamon law for borrower insurance and extended to other policies, lets you switch providers without waiting for the renewal date.
Renegotiating fixed contracts generates recurring savings, unlike cutting back on a one-off outing or purchase. Over twelve months, the difference between two energy suppliers or two health insurance plans can amount to several hundred euros, without affecting your standard of living.
- Compare at least three quotes for each insurance policy (home, car, health) before every annual renewal
- Check that your mobile or internet plan matches your actual usage (data consumed, calls, required speed)
- Ask for a rate review or renegotiate your mortgage if market conditions have changed since you signed
Variable expenses: the micro-optimization trap
Canceling a streaming subscription frees up a few euros a month. This often-touted step distracts from more significant trade-offs. Changing just one insurance policy can save more than a year of small cutbacks.
Managing variable expenses is still useful for households whose fixed costs are already optimized. For everyone else, it takes a disproportionate amount of effort for the savings involved.
Retirement savings plan: a real tax benefit or just a deferral?
The PER (retirement savings plan) has become increasingly popular in recent years. Its tax mechanics are appealing: voluntary contributions are deductible from taxable income, reducing your tax bill in the year you make them.
But the PER tax deduction defers tax; it does not eliminate it permanently. When you withdraw the money, as a lump sum or annuity, the amounts received are subject to income tax. If your marginal tax rate is the same in retirement, the net tax benefit is zero.
Liquidity and emergency savings
As a rule, money in a PER is locked away until retirement, except in cases of early release provided for by law (purchase of a primary residence, disability, death of a spouse, over-indebtedness, expiry of unemployment benefits, cessation of self-employment).
A PER is no substitute for accessible emergency savings. A household without a cash buffer in a savings account or an interest-bearing current account takes a risk by directing all its savings capacity into a locked-in product.
| Criterion | PER | Life insurance (euro-denominated fund) | Regulated savings account |
|---|---|---|---|
| Access to funds | Locked except in legally defined cases | Withdrawals possible at any time | Withdrawals unrestricted |
| Tax benefit on contributions | Contributions are deductible | None | None |
| Tax treatment on withdrawal | Income tax | Tax allowance after 8 years | Tax-exempt (within the limits) |
| Role in your assets | Retirement planning | Medium- to long-term savings | Emergency savings |
This comparison shows that each type of account serves a different need. Focusing your entire strategy on a single vehicle can create an imbalance between liquidity and tax efficiency.
Asset allocation: build in stages
Rather than aiming for a fixed, theoretical portfolio, an effective allocation is built by following priorities based on your actual financial situation.
- First, build emergency savings covering three to six months of fixed expenses in an accessible account (Livret A, LDDS)
- Open a life insurance policy invested in a euro-denominated fund for medium-term savings, benefiting from the tax holding period from the date the policy is opened
- Contribute to a PER only if your current marginal tax rate is higher than the one you expect to pay in retirement, and you have already built up emergency savings
- Consider diversified investments (SCPI, shares through a PEA) once the first two stages are secure
The order of these stages matters just as much as the choice of investments. Investing in SCPI or shares without a liquid safety net may force you to sell at the wrong time if an unexpected expense arises.
Preparing for your financial future is about more than choosing the right product. It means prioritizing your needs, taking an honest look at your savings capacity, and understanding the tax rules that apply when you withdraw your money—not just when you contribute.
