Teams get 2 unsuccessful reviews per innings in Tests (reset after 80 overs) and 1 in LOIs. Reviews are retained if the on-field decision is overturned.
Details
The DRS review allocation varies by format:
Tests: Each team gets 2 unsuccessful reviews per innings. If a review is successful (on-field decision overturned), the review is retained. Reviews are reset after 80 overs in each innings, meaning a team that used both reviews early can get them back.
ODIs: Each team gets 1 unsuccessful review per innings. Successful reviews are retained.
T20Is: Each team gets 1 unsuccessful review per innings.
IPL: Originally had no DRS, but adopted it in later seasons with 1 review per innings.
The allocation system encourages teams to use reviews wisely — frivolous reviews cost the team their right to challenge genuinely wrong decisions later.
Historical Evolution
The review allocation has changed over time. Initially, teams had more reviews, but this was reduced to prevent overuse and maintain the pace of the game. The 80-over reset in Tests was introduced to ensure teams weren't penalized for using reviews early in long innings.
Some have argued for unlimited reviews, arguing that getting decisions right should take priority over maintaining pace.
Current Rule
Tests: 2 unsuccessful reviews per innings (reset at 80 overs). ODIs/T20Is: 1 unsuccessful review per innings. Successful reviews retained.