Easiness to justify
Take the depreciation rate into account!
You are making a major investment: a new studio comes out of the ground, for example. You deduct this construction in proportion to your professional use.
You also take into account its depreciation rate. As an indication, for a building with an estimated lifespan of 30 years, the annual depreciation rate will be 3%.
Are you self-employed in a company? You should know that on 1 January 2020, a “pro rata temporis” depreciation came into force for all assets acquired from 2020 onwards. You therefore deduct in proportion to the remaining months in the year of your investment.
Are you self-employed as an individual? There is no pro rata temporis depreciation. Did you buy in October? You still amortize for the whole year.