Industry standard is 30 days warranty period.
If client is asking you for 60 days , you are increasing the risk and cost of your organization.
Remember job performance of any candidate is not the responsibility of consultant and these days only few employer will terminate the employee for non performance. If employee is non performer ( sales or business development position) after three to four months employer will ask the candidate to resign from the job. Even the candidate will find to better to resign then to get terminated.
Now in that situation as a consultant you need to do double work or refund the money ( loss for consultant).
If your prospect client is asking you for 6 months , you should have guts to refuse the deal.
Like to give you a practical example.
Some days back , even I had a meeting with a prospect client who asked me to provide 6 months replacement period or to work at 6% CTC if I am providing 3 months warranty period. Even the client was telling me there are 10 consultancies in India ( Brands) working for them and providing 6 months warranty period.
The question here is if brands are working for them , why they need more consultancies . Either the client is trying to take benefit or those consultancies are not providing service to them as they have experienced loss or they refuse to work above 3 months warranty period. Yes if you are freelancer or very much desperate to get clients you 'll work on wrong deal.
If the client is having policy of 6 months warranty then why as a consultant we should change our policy.
I refused to work with that client where replacement is above 90 days and believe me those client who cry for 1% or 2% are not at all worth to be worked with.
Its difficult to find good client but its not impossible . This refuse to work with these kind of prospects clients as thats a bad deal for the business.