Ideal situation is to have contingencies in place for every member of the company. Realistically it is relatively easy to have backups for producing employees w

Ideal situation is to have contingencies in place for every member of the company. Realistically it is relatively easy to have backups for producing employees where there are multiple in a team anyway - devs, ops, designers - than for managerial employees. (Managers groom their own backups iff they want to get promoted.) So if you are a flight risk, you are unlikely to become a manager or given any additional "unique" responsibilities in terms of tech-lead or customer-facing work, unless your skills are really extraordinary and indispensable (and usually they aren't).