Is the verification for SIPs a one-time process?

If you’re using a bank account that’s already verified through netbanking/debit card, you don’t have to complete the verification again for any new SIP. However, you would have to complete the verification if you use a bank account that’s not verified for SIP. 

If you’re using UPI, you will have to complete the verification for each new SIP. 

Learn more about the banks which allow auto payments for SIPs