A portal is worth having for exactly one reason: it gives the client a place to see and do their part without an email thread. Almost every disappointment in this category comes from portals that added a place without removing the thread, so the practice ends up maintaining both. What separates the two outcomes is not features, it is whether the portal is a view of the real record or a separate box beside it.
A view of the record, or a second place things live
If the portal shows the same client record the practice works from, then what the client uploads is immediately against that client and what the practice requests is immediately visible to them. If it is a separate system that syncs, you have two sources of truth and a reconciliation job nobody scheduled. Document portal software sold standalone is particularly prone to this, and the symptom is a practice that downloads from the portal and files it somewhere else, which is the whole benefit given back.
The outstanding list is the feature
Everything else a portal does is secondary to answering, for both sides, what is still needed. A client who logs in and sees three outstanding items with clear names will usually deal with them; one who sees a file tree will close the tab. That means the request list has to be per client, has to be maintained from the practice side without much effort, and has to visibly empty as things arrive. Portals that treat requests as an afterthought are the ones that fail to displace email.
Access ends, and the portal has to know that
Clients leave, contacts change roles, and a bookkeeper who had access last year should not have it now. A portal is a standing grant of access to real information, so the ability to see who currently has access to a given client, and to revoke it in one action, is not an advanced requirement. It is the thing that makes a portal safer than emailing documents around, and without it the portal is mostly a nicer-looking version of the same exposure.
Questions people ask about client collaboration portals
Does a client portal actually reduce email?
Only if the outstanding list is good enough that clients use it instead of replying. A portal with weak requests becomes a place you also have to check, which is worse than not having one.
Standalone document portal, or a portal on the client book?
A portal attached to the record you already work from avoids two sources of truth. Standalone document portals are quicker to adopt and tend to produce a download-and-refile habit that gives back the benefit.
What should we check about access?
That you can see, per client, exactly who has access today, and remove it in one action. Also what happens to a client's documents when their access ends, since that answer is rarely the obvious one.