Be careful not to overfund your 401ks/HSAs/or social security

I was told that, we can open personal or business credit cards but use them vice versa as long as books are clean. Meaning, we can open a CC under our personal name and exclusively use it for a specific rental property's expenses, and vice versa, we can open a CC under our business name and use it for our personal property, IF we are renting out rooms (co-living, ADU, etc), as long as we have clean books and clear categorizations? Is this true and correct?? @Ryan Bakke, CPA @Mason Kimball, CPA @Kevin Medina, CPA, MBA