2673 20160701171709.0 ASTROimport-830 Lampens, P. 2005 Are these observations really necessary? We draw the attention to some bright, double and multiple visual systems with long-period orbits currently lacking high-quality astrometric data and we present arguments for resuming astrometric observations of these apparently very classical systems. When - for any good reason - a thorough study of these is being undertaken, the importance of the coverage of the critical phases in the orbit by follow-up observations should once more be stressed. Frémat, Y. Astrometry in the Age of the Next Generation of Large Telescopes 338 2005 276 http://esoads.eso.org/abs/2005ASPC..338..276L published in NONREF