Why go through secondary first

Quitting a permanent contract to launch "blind" is one of the most expensive mistakes you can make in your career. Secondary activity offers 4 decisive advantages:

  • Safety net: your salary still covers your fixed costs
  • Reduced contributions: ~21% only on self-employed income if you stay below threshold
  • Real market validation: you know if you can actually sell, not just if "your idea is cool"
  • Easy pivot: if it doesn't work, you cancel and lose nothing

Define clear quantified goals

Testing without measurable goals = lying to yourself. Before launching, write down in black and white:

Month 3: first paying clientInitial validation
Month 6: €1,500 cumulative revenueMarket exists
Month 12: €800/month recurringActivity viable
Month 18: 50% of your net salaryConsider switch

These thresholds are indicative. Adapt to your sector (a senior consultant will aim higher, a content creator will need longer).

The switch threshold to main activity

Simple rule: your self-employed activity must be able to cover your current net salary + ~50% before considering the switch.

Why 50% more? Because:

  • You lose your employer who also pays your holidays, pension, smoothed withholding tax
  • You go from secondary contributions (~21%) to main activity contributions (~20.5% but on a much broader base)
  • You must build a safety reserve (at least 6 months of charges)
⚠️ Classic pitfall: switching as soon as secondary income "matches" net salary. In reality, your real purchasing power drops because you lose the employer cushion. Aim higher.

The signals saying "it's time"

✅
You refuse missions for lack of time The strongest signal: demand exceeds what you can deliver evenings and weekends. Without going full-time, you're stuck.
✅
Your secondary income is stable over 6+ months Not an exceptional one-off mission, but a regular flow — ideally with at least 2-3 recurring clients.
✅
You have 6 to 12 months of safety reserve To absorb a 2-3 month gap without panic. Otherwise you'll undersell your rates at first calendar dip.
✅
You've crossed the full social contributions threshold Above approximately €18,600/year of secondary income, you're already paying as main activity. Might as well benefit fully time.

The signals saying "don't quit your job"

❌
One big client = 80% of revenue If they leave, you sink. Diversify first, switch second.
❌
Your income depends on your ex-colleagues network Practical short-term but doesn't prove a market. First verify you can sell to strangers.
❌
You say "it'll boom when I'm 100% on it" 9 times out of 10 false. If you can't generate reasonable income in secondary with discipline, full-time won't solve a product-market problem.

In summary

Secondary activity isn't a "while waiting" phase — it's a real validation tool. Give yourself 12 to 18 months with quantified goals, and only switch when the numbers justify it, not when the urge is strong.

The Belgian status is generous on this front: take maximum advantage before the big jump.

⚖️ Disclaimer. This article provides general guidelines. Each situation (family responsibilities, sector, seniority, unemployment rights) modifies the decision. Discuss your plan with an accountant or activity transition specialist.

Official sources

INASTI — Secondary self-employed status
1819.brussels — Brussels entrepreneur support
VLAIO — Flemish entrepreneur support