The instrument does not keep the tune! – This is the most common problem, especially with instruments from the former USSR, which do not withstand any criticism due to the insufficiently dried and not quite high-quality wood from which the instruments were assembled, in addition, most instruments have already "lived out" their resource regardless of whether the instrument was played or not. The entire set of snare drums is replaced with new ones of larger diameter, tuned to 440, as well as a control tuning 1-2 months after replacing the snare drums, due to natural processes.