  Young Stellar Objects (YSOs) in the early evolutionary stages are very
embedded, and thus they emit most of their energy at long wavelengths such as
far-infrared (FIR) and submillimeter (Submm). Therefore, the FIR observational
data are very important to classify the accurate evolutionary stages of these
embedded YSOs, and to better constrain their physical parameters in the dust
continuum modeling. We selected 28 YSOs, which were detected in the AKARI
Far-Infrared Surveyor (FIS), from the Spitzer c2d legacy YSO catalogs to test
the effect of FIR fluxes on the classification of their evolutionary stages and
on the constraining of envelope properties, internal luminosity, and UV
strength of the Interstellar Radiation Field (ISRF). According to our test, one
can mis-classify the evolutionary stages of YSOs, especially the very embedded
ones if the FIR fluxes are not included. In addition, the total amount of
heating of YSOs can be underestimated without the FIR observational data.
