Either way, there have been many threads along these lines. The general consensus is that it is not a competition and the frequency of visits can vary according to lifestyle, health, personalities and expectations of all concerned.
The answer, as with most things in life, is to talk about it, and, if this suits you, perhaps to agree on a system of regular visits, but be flexible, and remember that they grow up quickly and very soon sleepovers or outings with the grandparents may be included.
Some parents are very wary of handing over their children. Some grandparents can be very irresponsible. It has all been covered on Gransnet.
Whilst the grandchildren are tiny and visits include all 3 generations, it may be prudent for the grandparents to stay in the background and let the little ones get to know the and let the come forward when they are ready.
This is probably more than the OP is asking, so I'll shut up now.
Whether you are the parent or the grandparent, aim to be open about everything and make firm decisions.
There is no single answer.