If you need assurance that your book of account is correct and give actual picture of financial position, you need audit. If you are looking for investment, VC always want audited financial balance sheet.Its mostly ignore by early stage startups and be on hurry when they are going to raise funding or being acquired.
Every private limited company is must need to get its accounts audited to ensure correct and actual view of the accounts.
All LLPs whose contributions exceed Rs. 25 Lakh or whose turnover exceed Rs.40 Lakh are required to get their accounts audited annually.
The purpose of Internal Audit is to assist the management to evaluate internal controls and improve the effectiveness of risk management. There are certain class of companies which have to mandatory conduct internal audit.
Tax Audit is required to be conducted by every person carrying on business whose Total Sales or Turnover year exceeds Rs. 1 Crore and by a person carrying on profession and his Gross Receipts from profession exceed Rs. 25 Lakhs in the previous year.