Incumbents can secure re-election by strategically raising the cost of reversing their policies, allowing low-ability office-holders to persist and weakening electoral accountability. We develop a dynamic electoral model with heterogeneous candidates in which policy choices endogenously generate switching costs that shape future electoral competition. This mechanism creates a novel channel of political entrenchment: incumbents can deter replacement not by outperforming challengers, but by making policy change sufficiently costly. We introduce midterm reviews ― an institutional device that allows voters to determine, during the term, whether an incumbent remains eligible for re-election ― which constrains this form of entrenchment. Midterm reviews weakly increase voter welfare and strictly do so when they screen out low-ability incumbents who would otherwise survive. More broadly, the mechanism strengthens democratic resilience by limiting institutional entrenchment and preserving effective electoral accountability. Extending the model to multi-member executives, we show that cabinet-level reviews mitigate collective entrenchment arising from joint cost-setting.