You're a great parent when you did your best. We all have different circumstances and can only make the best of it. With that said the irony in this for me is that the best parents are the ones who aren't parents yet but prepare themselves to be the best parents when its time, makes sense? Getting a good education, financially sound, etc. Will go a long way so you aren't worrying over those issues after having children.
I feel that you are a successful pareng whdn your children come to you for advice and want to know how you got through this phase or that phase when raising them. It is also a good sign when your children make great decisions that can help them for the rest of their lives.
For every other species, I suppose it's an easy question. You're a successful parent when your own offspring have offspring. That's the Game of Life, period.
For humans, I think you are successful if you have created a safe home environment for your children. Every person has a different potential and a good parent will do their best to put their children first and help them to achieve their best.
I keep the phrase 'The apple doesn't fall far from the tree'.
Your offsprings' action and decisions reflects how they were educated and brought up.
Their success is your success.
So if your offsprings are successfully will mean you were a successful parent.
If the other, then same goes.
I Think its all based on how well you provide for your children, and how they act. If you work hard and teach them respect, manners and life lessons, and they actually use that, then you did your job.
I would recomend a video in youtube called “educar con humor” Charles Capdevila (In Spanish)
To me is to help them develop their potential, whatever that may ne.