On paper there remains enough after the future housing instalment. In everyday life you have never regularly set this amount aside. A self-imposed savings trial can show which spending assumptions you have overlooked so far. It neither proves creditworthiness nor long-term affordability and does not replace individual financing.
Try out exactly the difference
First compare the current and the assumed future total housing burden on the same basis. Add expenses that are to be incurred in the new situation, and remove only those whose cessation is actually clarified. An additional loan instalment is not simply added to a current rent if that rent will later cease. A possible transitional period remains shown separately.
In the fictional case the currently comparably recorded housing burden is 1.100 euros, the planned later burden 1.450 euros. The difference is 350 euros. The household wishes to save this amount additionally each month. That is a chosen test value, not a recommended burden ratio.
Do not unknowingly make the test easier
The household agrees to record necessary expenses normally during the trial. It does not subsequently declare missed medical bills, postponed purchases or support for family as irrelevant. A draw on the previous emergency fund also belongs in the record.
A trial that only succeeds through new debt or using up other reserves has a different implication than regular saving from truly remaining income. That does not make the trial worthless. It shows the point where the original planning was incomplete.
Distinguish three possible outcomes
In the first month the 350 euros are saved in full from current income. In the second month 150 euros are missing because of a genuinely necessary expense. In the third the saving only succeeds because an annual fee has not yet been debited. The evaluation is not “passed twice”. It names the missing expense item and the timing difference.
Then create a corrected household budget. A shorter test may possibly not include annual bills, income changes or property works. Such burdens are explicitly added; an observed good month is not copied twelve times as a secure future.
Use the trial to prepare a decision
The trial is useful if its result is allowed to change your plan: a smaller search scope, later purchase, different spending or further clarification. Decide in advance at which observed shortfall you will review the previous plan. Otherwise a test becomes merely a search for confirmation. Keep the accumulated money once in the further overall planning; it is at the same time the result of the trial and an existing asset, not a double financing contribution.