Although the formula for staying out of hell is simple—don’t lose sanctifying grace and you’ll go to heaven—it is hard work to keep and grow sanctifying grace.
The renouncement of sin is difficult at times. Our lust of the flesh, the eyes, and the pride of life are very powerful. Much effort is required to overcome this triple concupiscence.
Furthermore, it is sometimes difficult to do the things that we know are good and will increase sanctifying grace in the soul. Such things include going to Mass, going to Confession, daily prayer, fasting, etc. Doing these kinds of activities are not always “honky dory!” They often require sacrifice.
So, in one sense, staying out of hell is easy. But from another perspective, it is difficult.
This is why Jesus teaches in Matthew 7:13-14 that the road leading to destruction is wide and the road leading to heaven is narrow and few travel it.
Hope that helps!