Easement in Gross

It is the right (or a permit) given to a party like to the utility company to install cables or check the piping.

The party holding it can release the rights, or the one who has given access to it, can nullify it. 

It remains valid for life but can be nullified, if the contract has an expiration date, or if the owner sells the property because the new owner may or may not agree to the same terms.

One should know the terms and rights in conditions of buying a property with existing tenants or buying commercial property for investment, or when you wish to know how to use / redesign the property if I own half a house what are my rights?

In such ownerships, a homeowner may allow the other to use a pathway into the woods but if the property is bought by another person, such rights are not automatically transferred.