diff --git a/TODO.md b/TODO.md
index bc64f0a..a8a9b73 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,10 +1,10 @@
 # TODO
 
-- [ ] Add react-router
 - [ ] Add redux
-- [ ] Prevent reducing talent points on a row when it is a dependency for points already spent in the next row
 - [ ] Prevent reducing talent points on a talent that is a requirement for another talent with points in it
 - [ ] Talent tooltips
-- [ ] Change class
 - [ ] Generate URL for chosen talents
-- [ ] Responsive on mobile
\ No newline at end of file
+- [ ] Responsive on mobile
+- [ ] Pretty ClassPicker
+- [x] Add react-router
+- [x] Prevent reducing talent points on a row when it is a dependency for points already spent in the next row
\ No newline at end of file
diff --git a/src/components/TalentSlot.tsx b/src/components/TalentSlot.tsx
index 152f3c2..6707bbe 100644
--- a/src/components/TalentSlot.tsx
+++ b/src/components/TalentSlot.tsx
@@ -68,4 +68,4 @@ export const TalentSlot: FC<Props> = (props) => {
 
 TalentSlot.defaultProps = defaultProps
 
-// ;(TalentSlot as any).whyDidYouRender = true
\ No newline at end of file
+;(TalentSlot as any).whyDidYouRender = true
\ No newline at end of file
diff --git a/src/data/talents.ts b/src/data/talents.ts
index f1dc5b5..3cabed2 100644
--- a/src/data/talents.ts
+++ b/src/data/talents.ts
@@ -3744,9 +3744,14 @@ export const talentsBySpec: Root = {
   }
 }
 
-export const talentToSpec: {[key: number]: number} = {} 
+export const talentsById: {[key: number]: TalentData} = {}
+export const talentsBySpecArray: {[key: number]: TalentData[]} = {}
+export const talentToSpec: {[key: number]: number} = {}
+
 for (let specId in talentsBySpec) {
   for (let talentId in talentsBySpec[specId]) {
+    talentsById[talentId] = talentsBySpec[specId][talentId]
+    talentsBySpecArray[specId] = Object.values(talentsBySpec[specId])
     talentToSpec[talentId] = parseInt(specId, 10)
   }
 }
diff --git a/src/lib/tree.ts b/src/lib/tree.ts
index 1f247de..e7e28fb 100644
--- a/src/lib/tree.ts
+++ b/src/lib/tree.ts
@@ -1,7 +1,8 @@
 import { List, Map, fromJS } from 'immutable'
-import { talentsBySpec, talentToSpec } from '../data/talents';
+import { talentsBySpec, talentToSpec, talentsById } from '../data/talents';
 
 export const MAX_POINTS = 51
+export const MAX_ROWS = 7
 
 /**
  * Returns the overall points spent in the tree.
@@ -36,13 +37,18 @@ export function calcMeetsRequirements(talent: TalentData, known: Map<number, num
 export const addTalentPoint = (known: Map<number, number>, talent: TalentData): Map<number, number> => {
   const currentPoints = known.get(talent.id, 0)
   
-  // Support for specific Talent dependency requirement.
-  if (talent.requires.length > 0 && !calcMeetsRequirements(talent, known)) {
+  // Reached the max rank?
+  if (currentPoints >= talent.ranks.length) {
+    return known
+  }
+
+  // Spend a maximum of 51 points
+  if (calcAvailablePoints(known) === 0) {
     return known
   }
   
-  // Spend a maximum of 51 points
-  if (calcAvailablePoints(known) === 0) {
+  // Support for specific Talent dependency requirement.
+  if (talent.requires.length > 0 && !calcMeetsRequirements(talent, known)) {
     return known
   }
   
@@ -52,11 +58,6 @@ export const addTalentPoint = (known: Map<number, number>, talent: TalentData):
   if (requiredPoints > pointsInSpec) {
     return known
   }
-  
-  // Reached the max rank?
-  if (currentPoints >= talent.ranks.length) {
-    return known
-  }
 
   return known.set(talent.id, currentPoints + 1)
 }
@@ -66,13 +67,41 @@ export const addTalentPoint = (known: Map<number, number>, talent: TalentData):
  */
 export const removeTalentPoint = (known: Map<number, number>, talent: TalentData): Map<number, number> => {
   const currentPoints = known.get(talent.id, 0)
-  
-  // TODO: We should prevent reducing talent points on a row when it is a dependency for points already spent in the next row.
+  const specId = talentToSpec[talent.id]
 
-  // Already no points for this talent
+  // No points to reduce for this talent
   if (currentPoints === 0) {
     return known
   }
+  
+  let highestRow = 0
+  let cumulativePointsPerRow = {}
+  known.forEach((points, talentId) => {
+    const t = talentsBySpec[specId][talentId]
+    if (t) {
+      highestRow = t.row > highestRow ? t.row : highestRow
+      for (let row = t.row; row < MAX_ROWS; row++) {
+        cumulativePointsPerRow[row] = (cumulativePointsPerRow[row] || 0) + points
+      }
+    }
+  })
+
+  // Check if removing this talent would not break the requirements for talents spent in later rows
+  const pointsUntilHighestRow = cumulativePointsPerRow[highestRow - 1]
+  const targetPointsHighestRow = highestRow * 5
+  if (talent.row < highestRow && pointsUntilHighestRow - 1 < targetPointsHighestRow) {
+    return known
+  }
+
+  // TODO: Prevent if another talent depends on this 
+  // const isDependency = known.reduce((prev, current, key) => {
+  //   if (prev) return prev
+  //   const t = talentsBySpec[specId][key]
+  //   if (t.requires.length === 0) {
+  //     return false
+  //   }
+  //   t.requires.map((d) => d.id === talent.id ? d : undefined)
+  // }, false)
 
   return currentPoints === 1 
     ? known.remove(talent.id)