Test of Enduring benefit is not certain or conclusive test. What is important is not that advantage lasts forever but whether the expense incurred does away with a recurring expense(s) defrayed towards running a business as against an expense undertaken for the benefit of the business as a whole. In other words, the expenditure which is incurred, which enables the profit-making structure to work more efficiently leaving the source of the profit-making structure untouched, would be an expense in the nature of revenue expenditure. Fine tuning business operations to enable the management to run its business effectively, efficiently and profitably, leaving the fixed assets untouched would be an expenditure in the nature of revenue expenditure even though the advantage may last for an indefinite period. Test of enduring benefit or advantage would thus collapse in such like cases. It would be only truer in cases which deal with technology and software application, which do not in any manner supplant the source of income or add to the fixed capital of the assessee-Asahi India Safety Glass Ltd. 203 Taxman 277 (Del.)