Tier position is usually decided by reporting
Most small teams upgrade within six months, and the trigger is nearly always a report or a forecast the manager wants. Write the reporting requirements before choosing a tier and ask which tier holds each view. It is far cheaper to start on the right tier than to migrate the team's habits twice.
Limits that bind quietly
Custom fields, number of pipelines, saved reports and active sequences are the usual ceilings. A new CRM always feels spacious, and these limits bind once real usage starts. Ask for the numbers in writing and compare them against what your team already tracks in spreadsheets today, which is a better predictor than what you imagine you will use.
Audience counting and send allowances
Ask whether unsubscribed and bounced records still count towards your band, whether suppression frees capacity, and how quickly. Then ask whether one-to-one sales email draws on the same monthly send allowance as campaigns, because a busy campaign month should not throttle the sales team.
Count the vendors, not just the features
List the channels you sell on and ask which are native. Each channel that needs another tool adds a subscription, a login, a connector and another support queue. For an SMB team the practical test is whether a manager can see calls, emails, messages and deal stage on one record without opening a second product.