I want to ordain temporarily as a monk sometime in the future because I want to experience what it’s like to live and practice a life of purity. I don’t know if I have the strength in me to ordain permanently because I’ve heard of those who disrobed even after attaining Jhana or some Vipassana knowledges. I also have a lot of attachments. However, I want to practice the Dhamma so that I can become a Paccekabuddha in a future life. It’s a goal that’s inspired me for years now. If I ordain temporarily, I will be happy when recollecting it for the rest of my life, but I feel that I will also regret disrobing. My question is, is it bad kamma to disrobe when you ordain as a monk? In my case, would it be better just to observe 8 precepts and practice meditation at a meditation retreat?
You could consider ordaining temporarily as a samanera (novice monk) first to learn the lifestyle. In the Theravada tradition, there is the practice of temporary ordination (pabbajja samanera), which allows one to experience renunciation firsthand. I’m not sure how common it is elsewhere, but in my country, short-term pabbajja programs are readily available and typically run for about two weeks.
If a program like that isn’t available where you live, you can simply cultivate meditation at home, both samatha and vipassana, especially if you don’t have the time to attend a formal retreat. Use samatha to build steady mindfulness (sati), reaching jhana isn’t necessary. With that grounded sati, observe the turbulences of the mind in everyday life. You will see that everything shifts from moment to moment and cannot be controlled, the very marks of anicca and anatta. You can reinforce this with formal seated meditation, watching the ever-changing nature of both body and mind.
Whenever you feel lost, return to the Suttas. While the Abhidhamma can serve as an analytical reference, it’s often much better to stick to the early discourses first because the language is straightforward and accessible. All the practical answers you need for your practice are right there.