Migrating from old to new core platforms remains one of the genuinely difficult problems in insurance technology. First-time core modernization projects routinely surprise their leaders. Core why insurance needs digital transformation systems encode decades of business logic, regulatory accommodation, and operational reality. They contain hundreds of edge cases nobody remembers building in. Regulatory adjustments stacked layer on layer all exist within the system being replaced. Migration efforts encounter this depth gradually throughout their lifecycles. Project boundaries that seem clear at the outset grow as analysis exposes more edge cases. Estimated timelines stretch routinely. This pattern is reliable enough that it deserves planning for, not lamenting. Better-performing initiatives build realistic schedules around what consistently happens. They favour incremental transitions over big-bang replacements. Newer business segments often migrate ahead of legacy books. This approach reduces risk. It also takes longer in nominal terms. The trade-off favours patience. Change management requires resources comparable to technical implementation. Operational staff adapting to changed workflows require investment in their adoption. The insurers achieving meaningful core modernization approach the work with appropriate realism about its scale and difficulty.