Highly skilled - expert understanding of their stack and very strong understanding of whole cs / whole stack(hw, fw, sw) / how computers work, etc Significant

Highly skilled - expert understanding of their stack and very strong understanding of whole cs / whole stack(hw, fw, sw) / how computers work, etc Significant experience - e.g >15 years across various projects/companies/teams Mature Responsible Curious Reasonable - uses pros and cons when evaluating solutions, not the latest stuff on his favourite software evangelist's blog