Whoever controls the grips controls the position.
The person with dominant grips will almost always control the position.
Note that this doesn’t apply to any grip, only dominant grips. A grip is dominant if it gives you more control over your opponent than your opponent gains over you.
Avoid grips that are non-dominant. You don’t gain control of your opponent just because you’ve established a grip. In fact, some grips are worse than useless because they give your opponent control over you (see body tethering).
As soon as your opponent establishes dominant grip control, you are on the defense and your opponent can begin advancing the position. This is why grip inversion is so important: you need to immediately regain dominant grips to stop your opponent’s positional advancement.