It’s important to be able to let go. In our daily life we have to let go to sleep, make love, or just enjoy the day. In meditation we have to let go in order to be fully present with ourself. Jhana and Enlightenment are basically the same, but with jhana you let go temporarily and with enlightenment you let go permanently. Let go of what? Of the attachments that obstruct you from being in perfect harmony, free and spontaneous to do anything you choose, from realizing universal consciousness. So then consider a short meditation period like 5 min compared with a longer one like 60 min. If you meditate for 5 minutes and spend them in jhana, that’s awesome, but unlikely for most persons. Instead some obstacle(s) will keep you from it, some anxiety you can’t let go, some concern you can’t stop worrying about, something in your environment or body that keeps grabbing your attention. In order to learn how to let go of those things you have to first separate yourself from them, and that requires applying keen investigation and holding steady clear perception of what the obstacles are. It does not require that you understand them or their mechanism; in fact that most always comes in hindsight. So don’t get lost in analytical reasoning and trying to “solve” for a solution. Well, when we meditate for a long time like 60 min, whatever we are holding on to that is holding us back starts to feel tired and worn out. That helps us perceive it. If we can hold our attention steady and crack ourselves open to let it go, then we’ve made the space for jhana. On the other hand we may get fully exhausted before we get that and have to try again another time. You may always exhaust without clearing the space, but don’t give up because anytime you might just let go and find it’s suddenly easy. After that experience, meditation practice becomes a real joy and new obstacles are welcome on the cushion and even in daily life. Eventually all obstacles are gone and you are just free and happy.