diff --git a/packages/relay/src/lib/services/hbarLimitService/index.ts b/packages/relay/src/lib/services/hbarLimitService/index.ts
index d66dc31c57..ff6d0860e4 100644
--- a/packages/relay/src/lib/services/hbarLimitService/index.ts
+++ b/packages/relay/src/lib/services/hbarLimitService/index.ts
@@ -209,41 +209,43 @@ export class HbarLimitService implements IHbarLimitService {
   /**
    * Add expense to the remaining budget.
    * @param {number} cost - The cost of the expense.
-   * @param {string} ethAddress - The Ethereum address to add the expense to.
+   * @param {string} [ethAddress] - The optional Ethereum address to add the expense to.
    * @param {string} [ipAddress] - The optional IP address to add the expense to.
    * @param {string} [requestId] - An optional unique request ID for tracking the request.
    * @returns {Promise<void>} - A promise that resolves when the expense has been added.
    */
-  async addExpense(cost: number, ethAddress: string, ipAddress?: string, requestId?: string): Promise<void> {
-    if (!ethAddress && !ipAddress) {
-      throw new Error('Cannot add expense without an eth address or ip address');
-    }
+  async addExpense(cost: number, ethAddress?: string, ipAddress?: string, requestId?: string): Promise<void> {
+    const requestIdPrefix = formatRequestIdMessage(requestId);
 
-    let spendingPlan = await this.getSpendingPlan(ethAddress, ipAddress);
-    if (!spendingPlan) {
-      // Create a basic spending plan if none exists for the eth address or ip address
-      spendingPlan = await this.createBasicSpendingPlan(ethAddress, ipAddress);
-    }
+    if (ethAddress || ipAddress) {
+      let spendingPlan = await this.getSpendingPlan(ethAddress, ipAddress);
 
-    const requestIdPrefix = formatRequestIdMessage(requestId);
-    this.logger.trace(
-      `${requestIdPrefix} Adding expense of ${cost} to spending plan with ID ${spendingPlan.id}, new spentToday=${
-        spendingPlan.spentToday + cost
-      }`,
-    );
+      if (!spendingPlan) {
+        // Create a basic spending plan if none exists for the eth address or ip address
+        spendingPlan = await this.createBasicSpendingPlan(ethAddress, ipAddress);
+      }
+
+      this.logger.trace(
+        `${requestIdPrefix} Spending plan expense update: planID=${spendingPlan.id}, subscriptionType=${
+          spendingPlan.subscriptionType
+        }, cost=${cost}, originalSpentToday=${spendingPlan.spentToday}, updatedSpentToday=${
+          spendingPlan.spentToday + cost
+        }`,
+      );
 
-    // Check if the spending plan is being used for the first time today
-    if (spendingPlan.spentToday === 0) {
-      this.dailyUniqueSpendingPlansCounter[spendingPlan.subscriptionType].inc(1);
+      // Check if the spending plan is being used for the first time today
+      if (spendingPlan.spentToday === 0) {
+        this.dailyUniqueSpendingPlansCounter[spendingPlan.subscriptionType].inc(1);
+      }
+      await this.hbarSpendingPlanRepository.addAmountToSpentToday(spendingPlan.id, cost);
+
+      // Done asynchronously in the background
+      this.updateAverageDailyUsagePerSubscriptionType(spendingPlan.subscriptionType).then();
     }
 
-    await this.hbarSpendingPlanRepository.addAmountToSpentToday(spendingPlan.id, cost);
     this.remainingBudget -= cost;
     this.hbarLimitRemainingGauge.set(this.remainingBudget);
 
-    // Done asynchronously in the background
-    this.updateAverageDailyUsagePerSubscriptionType(spendingPlan.subscriptionType).then();
-
     this.logger.trace(
       `${requestIdPrefix} HBAR rate limit expense update: cost=${cost}, remainingBudget=${this.remainingBudget}`,
     );
@@ -334,12 +336,12 @@ export class HbarLimitService implements IHbarLimitService {
 
   /**
    * Gets the spending plan for the given eth address or ip address.
-   * @param {string} ethAddress - The eth address to get the spending plan for.
+   * @param {string} [ethAddress] - The eth address to get the spending plan for.
    * @param {string} [ipAddress] - The ip address to get the spending plan for.
    * @returns {Promise<IDetailedHbarSpendingPlan | null>} - A promise that resolves with the spending plan or null if none exists.
    * @private
    */
-  private async getSpendingPlan(ethAddress: string, ipAddress?: string): Promise<IDetailedHbarSpendingPlan | null> {
+  private async getSpendingPlan(ethAddress?: string, ipAddress?: string): Promise<IDetailedHbarSpendingPlan | null> {
     if (ethAddress) {
       try {
         return await this.getSpendingPlanByEthAddress(ethAddress);
@@ -381,12 +383,12 @@ export class HbarLimitService implements IHbarLimitService {
 
   /**
    * Creates a basic spending plan for the given eth address.
-   * @param {string} ethAddress - The eth address to create the spending plan for.
+   * @param {string} [ethAddress] - The eth address to create the spending plan for.
    * @param {string} [ipAddress] - The ip address to create the spending plan for.
    * @returns {Promise<IDetailedHbarSpendingPlan>} - A promise that resolves with the created spending plan.
    * @private
    */
-  private async createBasicSpendingPlan(ethAddress: string, ipAddress?: string): Promise<IDetailedHbarSpendingPlan> {
+  private async createBasicSpendingPlan(ethAddress?: string, ipAddress?: string): Promise<IDetailedHbarSpendingPlan> {
     if (!ethAddress && !ipAddress) {
       throw new Error('Cannot create a spending plan without an associated eth address or ip address');
     }
diff --git a/packages/relay/tests/lib/services/hbarLimitService/hbarLimitService.spec.ts b/packages/relay/tests/lib/services/hbarLimitService/hbarLimitService.spec.ts
index e5dace01b4..7a9ce74714 100644
--- a/packages/relay/tests/lib/services/hbarLimitService/hbarLimitService.spec.ts
+++ b/packages/relay/tests/lib/services/hbarLimitService/hbarLimitService.spec.ts
@@ -628,20 +628,6 @@ describe('HbarLimitService', function () {
       sinon.assert.calledOnceWithExactly(incDailyUniqueSpendingPlansCounterSpy, 1);
     };
 
-    it('should throw an error if neither ethAddress nor ipAddress is provided', async function () {
-      const ipAddresses = ['', null, undefined];
-      const ethAddresses = ['', null, undefined];
-      const testCases = ethAddresses.flatMap((ethAddress) =>
-        ipAddresses.map((ipAddress) => ({ ethAddress, ipAddress })),
-      );
-      for (const { ethAddress, ipAddress } of testCases) {
-        // @ts-ignore
-        await expect(hbarLimitService.addExpense(100, ethAddress, ipAddress)).to.be.eventually.rejectedWith(
-          'Cannot add expense without an eth address or ip address',
-        );
-      }
-    });
-
     it('should create a basic spending plan if none exists', async function () {
       const newSpendingPlan = createSpendingPlan(mockPlanId);
       hbarSpendingPlanRepositoryStub.create.resolves(newSpendingPlan);