Despite of many advantages, double entry system has some disadvantages which are as follows:
(i) Double entry system is complex and hard to understand.
(ii) It involves time, labour and money, so it is not possible for small business to keep accounts under this system.
(iii) It required expert knowledge to keep accounts under this system.
(iv) As the system is complex, there is greater possibility of committing errors and mistakes.

(i) Matching principle states that the expenses of an accounting period are matched with the related revenue for correct determination of profit.
(ii) According to the matching principle, the purchase price of fixed asset is not related to the accounting period because the benefit derived from its use will be spread over a number of years.
(iii) Therefore, only depreciation related to the accounting period is considered for determination of profit

Value of consistency is reflected by the accounting standards issued by ICAI as following consistent set of standards, enables comparability of financial statements.

Yes, principle of conservatism has two effects.
(I) Profit and loss account discloses lower profit in comparison to the actual profits.
(ii) Balance sheet will disclose understatement of assets and overstatement of liabilities.

The need for accounting standards is as follows:
1. To Promote better understanding of financial statements.
2. To help accountants to follow uniform policies and practices.
3. To facilitate meaningful comparison of financial statements of two or more entities.
4. To enhance reliability of financial statements.
5. To meet the legal requirements effectively.