There’s no single answer, but this is an important consideration when framing your routine and rules. Remain flexible, especially if you are new to solitude, as the goal is not loneliness or suffering, but peace.
If you suffer from depression, anxiety, co-dependence, or addictive behaviors, I wouldn’t advise isolating too much. Try it in intervals, and work with a counselor to assist in resolving some of your personal challenges. Solitude can be a part of your healing process, but too much too soon and you can loose the self regulation and perspectives that enable you to keep afloat.
Weigh the dependence of others upon you. Don’t desert the people who you’re committed to helping, and don’t abandon your responsibilities. Hand off responsibilities if necessary, and find a way to continue supporting those who need you. Selfishness isn’t a part of the program.
Look at any loneliness with honesty and solvency in mind. Monastics are not necessarily friendless. Reach out when you need to. If you have no sympathetic friends, affiliate your efforts with a Unitarian Universalist group or similar in your area. If you love animals, consider volunteering at a rescue or wildlife rehab facility. If you battle loneliness regularly, join a group that is activity- or charity- focused that meets on a predictable basis. Community kitchens, Habitat for Humanity, municipal bands, bird watching clubs, board game circles, community gardening clubs, volunteer as a tutor, and so on.
Exercise is also important for mental health. Blowing off steam with intense activity, or using the repetitive rhythms of endurance activities to move thoughts along can do wonders for the mood. Don’t for get that your body supports your mind, too!
These things said, some people are very well equipped for solitude. I can spend months with no social contact, only a few sparse administrative contacts. However, I do schedule in some check-ins with a couple good friends monthly so to alleviate any concerns or because I may be of assistance. My solitude is also periodically interrupted by a visitor. Interestingly, since I’ve given my life this structure and purpose, it seems the perception of me within my community is that I’ve become not only a bit nutty, but also wise. The visitors often come to talk about deeply personal things that are troubling them, and they speak in trust and confidence.
Your approach to solitude should be flexible and individualized. I am a solitary. Most monastics are significantly more integrated into communities. Enough solitude is beneficial. Too much is not necessary and poses unnecessary challenges and misery.