End User License Agreements are important for protecting the rights of the business owner/licensor and critical for setting the rules of use and managing the expectations of the end-user.
Generally, the EULA will help you to set the conditions of your license agreement with the user – explain what they are and aren’t allowed to do with the software, the conditions under which their access might be limited or terminated, copyright provisions etc.
Some additional instances where you might need a End User License Agreement are where you:
need to make legally required disclosures related to consumer rights (especially withdrawal and cancellation rights);
have different user levels (eg. registered vs non-registered);
your platform allows users to sell or trade with other users;
facilitate or otherwise process payments and/or other sensitive user data; want to set the rules for user behavior and state grounds for termination of accounts;
participate in affiliate programs;
provide a software or service which can potentially cause harm if misused;
would like to have some legally enforceable control over, and set rules about, how your website/app/product may be used.