Article 12 of the KSA Income Tax Law establishes the general principle for the deductibility of business expenses. It permits taxpayers to deduct all regular and necessary expenses incurred during the taxable year for the purpose of generating taxable income. The provision applies to expenses whether they are paid or accrued within that period. However, this deductibility is subject to specific limitations outlined within the legislation. The Article explicitly excludes outlays of a capital nature and other non-deductible expenses, cross-referencing the specific prohibitions detailed under Article 13 of the Law and other relevant provisions.