Replenishment is a gameplay mechanic in the Total War series. It is the process in which regiments that are under full strength refresh their numbers.

Empire: Total WarEdit

In Empire: Total War, replenishment is manually activated by a button on the right of the army tab when an army is selected. All regiments, regardless of unit type, replenish in two turns with all units being added at the end of the second turn. Replenishment costs money: the heavier the unit's losses prior to replenishment, and the more expensive the unit type, the more money is required to replenish a regiment. Replenishment is generally cheaper than training new units from scratch. It can reduce the experience of a regiment (the new soldiers added are counted as completely inexperienced troops).

Replenishment can only be activated if there are sufficient funds available. In cases where an army cannot replenish and faces an imminent threat, it may be more prudent to merge units, instead. Merging troops instead of replenishing can also help preserve the experience levels of more veteran units.

Napoleon: Total WarEdit

Replenishment is completely revamped in Napoleon: Total War. Instead of being manually activated, it occurs automatically for free, and it no longer always takes two turns. Instead, multiple factors influence the rate of replenishment. Replenishment is denoted by a plus symbol next to the unit card on the world map. The color of the icon determines how quickly the unit is replenishing (red means a very slow rate of replenishment; green is very fast). 

On large unit size settings, most factions have a default replenishment rate of about 4% per turn. Units replenish at least one unit per turn, if their regiment sizes are so small that 4% a turn would replenish less than one. France has a hidden bonus of having its troops replenish more quickly than units from other factions: depending on unit type, base replenishment for the French is about 7-8%. This, in addition to France's generals having the General of the Grand Armee trait that further increases their replenishment by 5%, means that France's troops initially replenish much more quickly. While this gives them an edge numerically, it has the detrimental side-effect of increasing the risk of experience bleed from over-rapid replenishment.

Buildings such as farms, roads, and especially supply posts boost rates of replenishment. The Russian unique building, the Minin Monument, gives a global replenishment rate increase. Certain technologies and traits increase replenishment. Finally, regions that can train a certain unit type allow that type to replenish faster (for example, if a region can train Musketeers but not Silesian Schuetzen, and an under-strength regiment of each rest in that region, the musketeers replenish more quickly). Increases to replenishment rates are displayed as percentages. This is not a percentage of default replenishment (which would be miniscule if it were the case); instead, the replenishment percentage refers to the percentage of a regiment's full strength. A line infantry regiment at 50% strength and in a region with a +25% replenishment rate would fully recover in two turns, for instance.

Replenishment is impacted very minimally by region wealth. An extremely rich region replenishes units at a slightly faster rate than a very poor region. 

Units owned by the player only replenish in allied or player-owned regions, and only when stationed in a town or when led by a general. Certain general traits grant faster replenishment. Units suffering from attrition do not benefit from replenishment. Replenishment in allied regions is much slower than replenishment in owned regions. Units controlled by the A.I can replenish without a general.

Below is a chart of buildings, technologies, and traits that increase replenishment rates. Bolded rates are global increases, while un-bolded rates are region-specific. All rates are positive; there are no negative replenishment factors in Napoleon: Total War.

Basic Roads (building) Cobbled Roads (building) Metalled Roads (building) Supply Post (building) Supply Warehouse (building) Supply Depot (building)
1% 3% 5% 8% 14% 22%+1% global
Farms (building) Clearances (building) Great Estates (building) Minin Monument (building) Field Ambulances (technology) Logistics (technology)
1% 3% 5% 5% 4% 2%
Citizen Recruitment Initiatives (technology) Guerrilla Training Network (technology) Local Recruitment Initiatives (technology) General of the Grand Armee (trait)
5%  5% (guerrilla units only) 10% (auxiliary units only) +5%

No region can have more than one type of road, and no region has more than one farm; only one region (Brandenburg) can build more than one supply depot.