This study investigates expenditure- and tax-based consolidations under the rule of reductions in debt-to-GDP ratios to the target level and the effects of these consolidations on fiscal sustainability and welfare, using an overlapping generations model with exogenous growth settings. We derive (i) a threshold (ceiling) of public debt to ensure fiscal sustainability, (ii) sustainable paces of these consolidations, and (iii) the optimal pace of consolidations under both expenditure- and tax-based consolidations, examining whether these consolidations are effective in the sense that they are sustainable, increase welfare, and induce fairness of welfare distribution across generations (lower intergenerational conflicts over welfare). We find that the pace of tax-based consolidation required to ensure fiscal sustainability is higher than that required for expenditure-based consolidation. As for welfare, countries may differ in their choice of the type of consolidation, which depends on the size of outstanding debts relative to capital, the economy’s productivity, tax rate levels, and the extent of utility derived by individuals from public goods and services. More importantly, it may also depend on whether policymakers emphasize social welfare or fairness of welfare distribution between generations. By contrast, a common result from the viewpoints of both social welfare and fair distribution of welfare across generations is that fiscal consolidation cannot persist much longer than 30 years (one period in the model). This result will support the pace of consolidation in the EU: the Stability and Growth Pact.