l Magnification Range: The range of magnifications required for your specific applications.

l Resolution: The ability to distinguish fine details in the specimen. Higher resolution is crucial for detailed analysis.  

l Working Distance: The distance between the objective lens and the specimen. This is important for working with uneven or bulky samples.  

l Illumination: 

1. Type of light source: Halogen, LED, or other options.

2. Intensity and control: The ability to adjust the light intensity is essential for optimal image quality.

l Ergonomics: 

1. Comfort and ease of use: Consider factors like the microscope's height, stage movement, and eyepiece adjustments.  

l Budget: 

1. Determine your budget and choose a microscope that fits within your financial constraints.

I guess you might also want to read the article called Biological Microscope vs. Metallurgical Microscope: Main Differences and Similarities.