I have been following the mobilization as best I can since September. I think the Russians took in over 400,000 reservists and conscripts since the announcement of partial mobilization. Conscript class 2022-2023 is 120,000 men. Last year's conscript class is fully trained. However the Russians cannot legally use them.
The Russian economy is also getting mobilized with new production orders and coordination. The Russian defense budget for 2023 (9% of GDP) is approx. 3 times that of 2020 and 50% greater than 2021.
The last Russian MOD claim was 50,000 men in the front line and 80,000 training in the rear of the SVO. For the past 2 months the Russians have used reservists only marginally in combat, mainly in the defense and in support of attacks.
They and the Russian army (most of it withdrawn from Ukraine since July) is chiefly focused in training and integrating this mass of men and material. If they follow Russian doctrine they will refurbish tanks/IFV (they have 17,000 tanks in storage, and also production/refurbishment orders for T-62, T-72, T-90M) and expand their operational artillery forces from equipment they have in storage.
2021 IISS figures, Russia:
4,684 operational heavy artillery pieces (towed and self-propelled) and 180 heavy mortars (120mm towed and self-propelled).
876 operational MLRS.
12,415 heavy artillery pieces in storage. 3,320 MLRS in storage. 1,540 mortars in storage.
In Ukraine it has been claimed that Russia has been using approx. 3000-2000 artillery pieces.
The key is whether or not Russian army can create logistical support for, say 120,000 shells a day rather than 60,000. They can retake what is left of the annexed regions and claim a halfway-political victory with a conservative approach to a build-up.
A more intensive approach would be to finally use brigades and divisions in Ukraine. This would require large scale maneuvers, like Volstok with Eastern Military district in the fall. (50,000 troops, 6,000 vehicles). There is to be manuevers in Belarus. But all of this takes a lot of time.
The Russian MOD claimed that refresher training (2 months) is completed for 300,000 troops with 8,000 crews of various types. After this they are further layers of training. Some are sent to Ukraine, others are in the interior. My chief ???? is what this training is composed up and how big the Russian army in Ukraine is meant to be.
If they do full training with brigades and divisions (there was news that 3rd Motorized division completed training in Belarus) then they can actually open up a new front. The remainder of the annexed regions can be taken with increased force buildup with piecemeal reinforcements (as they are slowly doing now).