Salesforce Custom Development allows organizations to create tailored solutions that meet their specific business needs, but without expert guidance, challenges can occur such as:

1. Requirements gathering: Gathering and defining business requirements can be challenging, especially if stakeholders have varying and conflicting opinions.

2. Scope management: Defining and managing the scope of the project can be a demanding process, when stakeholders request additional features and functionalities.

3. Technical complexity: Developing custom solutions in Salesforce can be technically complex, especially when integrating with external systems and building complex business entities.

4. Testing: Testing the custom development to ensure it meets the requirements and specifications can be an arduous task, particularly when dealing with large and complex systems.

5. Security: When dealing with sensitive information, it can be tough to guarantee the security of custom development and safeguard user data and information.

6. Integration: Integrating the custom development with other systems and platforms can be challenging, especially if the data and authentication requirements are complex.

7. Documentation: Documenting the custom development, including code, data models, and business logic, can be time-consuming and require additional resources.

8. User adoption: Encouraging users to adopt and engage with the custom development can be an important consideration, especially if there is no clear value proposition or benefit for the users.

9. Maintenance and updates: Maintaining and updating the custom development with new features, bug fixes, and platform updates can be a challenge, mainly for organizations with limited IT resources.

10. Performance optimization: Optimizing the performance of the custom development can be demanding, mostly when dealing with large and complex systems.