Russia recruits replacements from 18 to 60 years old

 ISW:

The Russian Federation has launched a large-scale drive to form volunteer battalions in the 85 “federal subjects” (or regions) that comprise the federation. Recruiting for some volunteer battalions began in June but has intensified in July, with new volunteer units being reported daily. The battalions apparently will consist of roughly 400 men each aged between 18 and 60. They will belong to various branches of service including motorized rifle, tank, and naval infantry, but also signals and logistics. Recruits are not required to have prior military service and will undergo only 30 days of training before deployment to Ukraine.

This recruitment effort will likely be expensive if it comes close to meeting its targets. It appears that the Russian Ministry of Defense will pay the volunteers’ salaries while the “federal subjects” will pay their enlistment bonuses. Salaries generally start at roughly $3,000 per month per soldier or about $1.2 million per month per 400-man unit. Enlistment bonuses offered by at least some units appear to be roughly a month’s salary. If the effort generates 85 battalions each of 400 men it would bring an additional 34,000 volunteers into the fight at the cost of about $102 million per month in salary alone. Considering that the 30 days of training the volunteers will receive before entering combat will not produce combat-ready soldiers, that price is very high. The volunteers will receive veteran status and benefits if they serve in Ukraine, moreover, in addition to their salaries and bonuses, a commitment that will add to the Russian Federation budget for decades.

This drive will likely produce “soldiers” of lower quality than the normal conscripts in the Russian army at close to professional-soldier prices. It is a remarkable expedient that suggests that Russian President Vladimir Putin remains unwilling to compel his people to fight and unable to attract them to fight voluntarily without considerable incentives.
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It is hard to imagine that these recruits will be front-line troops. They may be able to step in for support operations, but expecting them to engage in assault or even defensive operations would be a stretch.

ISW also reports that Russia has lost four airborne deputy commanders in Ukraine's HIMARS rocket attacks.

Ukrainian HIMARS strikes have likely killed or wounded four Russian 106th Airborne Division deputy commanders. Russian news outlets reported the deaths of 106th Division’s deputy commanders Colonel Sergey Kuzminov, Colonel Andrey Vasiliev, and Colonel Maxim Kudrin, seemingly confirming Ukrainian claims that HIMARS strikes on Shaktarsk on July 9 killed or wounded a significant portion of the 106th's leadership.[2] Ukraine’s Center for Strategic Communications claimed on July 12 that one unspecified 106th Airborne Division deputy commander remains in critical condition.[3]

Russia is not going to be able to replace these kinds of losses with conscripts at this point.  Perhaps they can promote people from the ranks but they have had significant leadership casualties for the duration of this war. 

See, also:

Ukraine strikes significantly reducing Russia's offensive potential, Kyiv says