Time Machine

I’m trying to use Time Machine for incremental backups to My Passport for Mac (i TB).  OS 10.7.5. I am succeeding sporadically, but there are problems. So let me just post a question: What is the best method for me to do an incremental backup, using Time Machine manually when the spirit moves me? Any guidance gratefully accepted. Thanks.

Just setup a schedule backup daily, weekly or monthly depending on your needs

Thanks very much for your suggestion, but, as stated in my question, I’d like to be able to back up manually as needed, and when I instruct Time Machine to “back up now,” it isn’t functioning well. What I need to know is the correct procedure for doing incremental backups off-schedule. Any advice?

If backup now is not functioning well you should try apple support