I have content where in I have to send the email notification or several reminders at different time points:
Ex: After saving content, email should send after 1month. 
then after 6 months for the same content.
then once every 5 years.
I have tried with node expiry module but it displays content expiry, and when we run the cron at that time only its able to send the mail,user cant run the cron every time sometime he may forget though.

Also I tried with rules schedule but I am not getting exactly what I want. can any one know how to resolve this issue.please help me.