Can a person with a life estate rent the property to others? Can remainder owners complain?
The holder of the life estate is responsible for paying taxes, maintaining the property in good repair, and not permitting it to suffer any "waste" or other damage. As long as the life tenant fulfills these duties, no other owners have a basis to complain.
With a life estate, someone owns the remainder interest in the property. (This person is sometimes called the remainderman.) That means that after the person with a life estate dies, the owner of the remainder interest will own the full interest in the property. If the owner of the remainder interest is concerned about the use of the property, for example, that renting might result damage and a loss of value, the owner of the remainder interest can always try and negotiate to buy the life estate and regain full ownership while the life tenant is still alive.