Enterprise territory management vs Sharing rule

Question

We have a requirement to share the accounts based on the region, cluster and territory they are in to the users. Right now, we have roles based on the region. Region, Cluster and Territory are custom fields and are populated based on the BillingCountry. We have close to 80k accounts right now. I am exploring the possibility of using Enterprise Territory Management to share the records based on country and replicate the region, cluster and territories as ETM territories, so that I can move away from the custom territory management setup.

My concerns on ETM so far:

1. Will we run into performance issue if the accounts grow?

   1.1. Considering the no.of share records created for ETM compared with Sharing rule(criteria based and shared with roles and subs) is high.

2. I saw that to make the account assignment rules run on edit we have to check this field : "Evaluate this account against territory rules on save". On the downside, as per the docs checking this field will run assignment rules on all accounts(https://trailhead.salesforce.com/en/content/learn/modules/advanced-territory-management/optimize-enterprise-territory-management-performance). I am not sure why assignments as to run all accounts?

In general for larger orgs, may I know which solution(ETM vs sharing rule) would be better in terms of performance and scalability?

Answer 1

I have implemented territory management to replace role-based sharing in an instance with about 2 million accounts. It seems to be working OK.

In terms of account assignment rules, it's very important to note that the rules do not run when an account is updated via API and its rule criteria fields change (i.e. through integration, data import, etc). Furthermore, there are no standard Apex methods for running the assignment rules, whether a single account or a collection.

This means your Apex trigger has to make an API callout (PATCH) for an account when its criteria fields change.