<p>This study examines how the length of post-retirement life affects individuals’ consumption-saving behavior in relation to the optimal consumption path. We conducted a laboratory experiment in which participants solved a simple life-cycle consumption–saving problem without uncertainty or volatility in interest rates, prices, or income. Lifetime was divided into working periods with constant income and retirement periods with no income. The experiment featured three treatments that varied the length and timing of retirement while holding lifetime income constant: <i>LS</i> (<i>long</i> working and <i>short</i> retirement) (5 retirement periods out of 25), <i>LL</i> (<i>long</i> working and <i>long</i> retirement) (16 out of 36), and <i>SL</i> (<i>short</i> working and <i>long</i> retirement) (16 out of 25). Across all the treatments, the participants’ consumption consistently deviated from the optimal consumption path in both the working and retirement periods. Although these deviations decreased after retirement, they persisted. Participants in <i>LL</i> and <i>SL</i> made larger absolute errors than those in <i>LS</i> during both periods, and their tendency to over-save after retirement was significantly greater relative to <i>LS</i>. These results suggest that extending the length of post-retirement life can result in systematic bias toward over-saving behavior, even in the absence of uncertainty.</p>