https://www.iiss.org/online-analysis/military-balance/2024/02/equipment-losses-in-russias-war-on-ukraine-mount/
An excerpt:
Bottom line
Despite losing hundreds of armoured vehicles and artillery pieces per month on average, Russia has been able to keep its active inventory numbers stable. For 2023, we estimate that Russia was able to reactivate at least 1,180 to 1,280 MBTs and around 2,470 IFVs and APCs from storage. On top of that, Moscow was able to manufacture new tanks and other armoured vehicles, though precise numbers are difficult to glean even from satellite images.
Commercial overhead imagery does shed light, though, on Russian equipment in storage that is potentially available for activation or refurbishment to compensate for further battlefield losses. Russia has 10 Central Tank Reserve Bases, at least 37 mixed equipment- and armaments-storage bases, and at least 12 artillery-storage bases. An in-depth assessment by the IISS last year showed equipment replenishments were roughly keeping pace with battlefield attrition.
It is our assessment, therefore, that Russia will be able to sustain its assault on Ukraine at current attrition rates for another 2–3 years, and maybe even longer.