To build a complex MIS dashboard in Google Sheets for tracking IT asset utilization across over 50 locations, I would start by structuring the solution in several key phases. First, I would ensure that we have a robust data collection process in place. This involves collaborating with the teams at each location to standardize data entry formats and methods, ensuring consistency and accuracy from the outset.

Next, I would focus on data validation. Given the volume of data, it's crucial to implement validation rules within Google Sheets to catch errors early. This could include using data validation tools to restrict inputs to certain formats or ranges, and employing conditional formatting to highlight any anomalies.

Once the data is validated, I would move on to data cleaning. This step involves removing duplicates, correcting inconsistencies, and filling in any missing values. Clean data is essential for accurate analysis and visualization.

With clean data, I would then structure the dashboard using Google Sheets' powerful features like pivot tables, charts, and scripts. The goal is to create an intuitive and interactive dashboard that allows users to easily filter and drill down into specific data points. I would also ensure that the dashboard is user-friendly for non-technical stakeholders by using clear labels and straightforward navigation.

In terms of challenges, I anticipate issues with data quality due to the diverse sources and potential human error in data entry. To mitigate this, continuous training and support for data entry personnel would be essential. Additionally, ensuring the dashboard remains responsive and performs well with large datasets could be a challenge, which I would address by optimizing formulas and using efficient data structures.

Finally, I would focus on ongoing maintenance and updates to the dashboard, incorporating user feedback to improve functionality and ensure it continues to meet the organization's needs.