Wearing 24/7 around other people, I like to stay really fresh, so I tend to change a bit more often than many other people seem to report, and rarely get close to leak-point. I don't have a rigid routine but as a guide:
1. Change out of night nappy when I get up and shower.
2. Usually make a mess after breakfast so I change again and use the bidet or jump back in the shower to get really clean before going out.
3 & 4. Some combination of morning, after lunch and afternoon, depending on how much I have to drink and whether there are any messes.
5. Evening, e.g. before going out.
6. Shower and change into night nappy before bed.
If I go out and have a lot to drink, another change may be needed during the evening. With this frequent changing, I have a carefree, leak-free life and no skin irritation. The other benefit of never using a nappy to full capacity is that if my schedule changes suddenly, as it often does, there is usually plenty of absorbency in reserve so that the need to change doesn't hold me up. If an ideal opportunity to change presents itself ahead of time, I change.