This study presents the first sensitive L-band survey of three intermediate-age (2.5–30 Myr) star-forming clusters: NGC 2264, NGC 2362, and NGC 1960. Using JHKL colors, the researchers determine the circumstellar disk fractions in these clusters, finding 52% ± 10%, 12% ± 4%, and 3% ± 3%, respectively. Combined with previous results from younger clusters (NGC 2024, Trapezium, and IC 348), the study provides the first systematic and homogeneous survey of disk fractions in a sample of young clusters spanning a wide range of ages (0.3–30 Myr) and containing statistically significant numbers of stars across the stellar mass spectrum. The results show that the initial disk fraction is very high (≥80%) and rapidly decreases with cluster age, such that half the stars lose their disks within ~3 Myr. The overall disk lifetime in the surveyed clusters is ~6 Myr, which is the timescale for essentially all stars to lose their disks. This timescale is critical for understanding the planet formation process in stellar clusters. The study also discusses the implications of these results for current theories of planet formation. The disk lifetime of ~6 Myr sets a meaningful constraint for the planet building timescale in stellar clusters. The results suggest that the initial disk frequency is relatively high (f_i > 50%), and that disk lifetimes are relatively short (3–15 Myr). However, these studies have limitations, such as incomplete samples and uncertain age determinations. The current survey addresses these limitations by using L-band observations, which are more sensitive to disk-bearing stars and allow for a more accurate determination of disk lifetimes. The results indicate that disk lifetimes are a function of stellar mass, with higher mass stars losing their disks faster than lower mass stars. The study also notes that the age of NGC 2362 is dependent on the turnoff age of a single star, which introduces some uncertainty. However, the overall disk lifetime of ~6 Myr is consistent with other estimates and supports the idea that the disk evolution timescale is critical for planet formation. The study also highlights the importance of dust in disk evolution and its role as a tracer of gas in the disks. The results suggest that the disk evolution timescales derived from the L-band survey likely characterize the bulk of the disk material around a young star and, consequently, should place important constraints on the timescale allowed for building gas giant planets around such stars. The study also discusses the implications of these results for current models of planet formation, including the core accretion model and the gravitational instability model. The results suggest that the disk lifetime of ~6 Myr is a critical constraint for the planet building timescale in stellar clusters.This study presents the first sensitive L-band survey of three intermediate-age (2.5–30 Myr) star-forming clusters: NGC 2264, NGC 2362, and NGC 1960. Using JHKL colors, the researchers determine the circumstellar disk fractions in these clusters, finding 52% ± 10%, 12% ± 4%, and 3% ± 3%, respectively. Combined with previous results from younger clusters (NGC 2024, Trapezium, and IC 348), the study provides the first systematic and homogeneous survey of disk fractions in a sample of young clusters spanning a wide range of ages (0.3–30 Myr) and containing statistically significant numbers of stars across the stellar mass spectrum. The results show that the initial disk fraction is very high (≥80%) and rapidly decreases with cluster age, such that half the stars lose their disks within ~3 Myr. The overall disk lifetime in the surveyed clusters is ~6 Myr, which is the timescale for essentially all stars to lose their disks. This timescale is critical for understanding the planet formation process in stellar clusters. The study also discusses the implications of these results for current theories of planet formation. The disk lifetime of ~6 Myr sets a meaningful constraint for the planet building timescale in stellar clusters. The results suggest that the initial disk frequency is relatively high (f_i > 50%), and that disk lifetimes are relatively short (3–15 Myr). However, these studies have limitations, such as incomplete samples and uncertain age determinations. The current survey addresses these limitations by using L-band observations, which are more sensitive to disk-bearing stars and allow for a more accurate determination of disk lifetimes. The results indicate that disk lifetimes are a function of stellar mass, with higher mass stars losing their disks faster than lower mass stars. The study also notes that the age of NGC 2362 is dependent on the turnoff age of a single star, which introduces some uncertainty. However, the overall disk lifetime of ~6 Myr is consistent with other estimates and supports the idea that the disk evolution timescale is critical for planet formation. The study also highlights the importance of dust in disk evolution and its role as a tracer of gas in the disks. The results suggest that the disk evolution timescales derived from the L-band survey likely characterize the bulk of the disk material around a young star and, consequently, should place important constraints on the timescale allowed for building gas giant planets around such stars. The study also discusses the implications of these results for current models of planet formation, including the core accretion model and the gravitational instability model. The results suggest that the disk lifetime of ~6 Myr is a critical constraint for the planet building timescale in stellar clusters.