Phased Design Fees and a Facility-Support Retainer on One Account

One-time invoice, not a subscription. Each phase, schematic design, design development, construction documents, construction administration, represents a defined percentage of the total fee negotiated up front, triggered by the project reaching that phase rather than by a calendar date. A subscription implies a recurring cycle that doesn't describe how phased architectural fees actually work. Bill each phase as its own one-time invoice when the client approves that phase's deliverables, and keep the total fee schedule visible in your project accounting so both you and the client can see how much of the total has been billed at any point.

A monthly facility-support agreement, ongoing consultation on building systems or space planning after occupancy, is genuinely recurring in a way the phased design fee isn't, and it fits a standard subscription in either Stripe Billing or Chargebee well. Set it up as its own billing object entirely separate from the phased design fee, even if it's the same client and the same project relationship. The two behave completely differently: one is a fixed total split into milestone payments, the other is an open-ended monthly charge until either side ends it.

Construction administration in particular can stretch well beyond its original estimate if a project's construction schedule slips, and that phase's fee is typically billed incrementally as work continues rather than in one lump sum at the start. If that incremental CA billing and a monthly facility-support retainer are running on the same account at the same time, keep them as visibly distinct charges on the invoice, or as separate invoices entirely, so a client reviewing their bill can tell which dollars are paying for construction oversight and which are paying for the ongoing retainer, rather than seeing one large combined number and questioning what it covers.

Not automatically. If a project gets value-engineered down partway through, reducing the total construction cost and, by extension, a fee calculated as a percentage of construction cost, that recalculation happens in your own project accounting, not in either billing platform. Once the new total fee is agreed with the client, adjust the remaining phase invoices to reflect it going forward; don't try to claw back what's already been invoiced for completed phases unless the engagement letter specifically allows for it.

Stripe Billing's lower setup cost and simpler configuration usually fits a studio where phased design fees, essentially one-time invoicing with a defined schedule, make up most of the revenue and facility-support retainers are a smaller side of the business. Chargebee starts to earn its cost once a firm has enough facility-support and ongoing consultation retainers that a practice manager needs to handle pauses, price changes, and renewals across several accounts without pulling a principal architect into every billing decision.

Say a studio is billing the construction documents phase, twenty percent of the total design fee, on a project where the client also pays a separate monthly facility-support retainer for a different, already-occupied building. The phase invoice should reference the total fee schedule, showing what's been billed to date and what remains, while the retainer invoice stands entirely apart with its own billing date and its own scope. A client reviewing both should be able to tell at a glance that one is progress against a fixed total and the other is an ongoing monthly charge with no defined end, rather than wondering whether the two are somehow related. That clarity matters most at year-end, when the firm's own accountant needs to separate project-based fee revenue from true recurring retainer revenue for financial reporting, a split that's far easier to pull from clean records than to reconstruct from a year of combined statements. Build that habit early, even on a firm's first facility-support client, rather than retrofitting clean records after a few years of combined invoices have already piled up.

Keep phased fees and the retainer legible on one account with these rules:

• Bill each design phase as a one-time invoice once the client approves that phase's deliverables, not on a calendar schedule.
• Set up the facility-support agreement as its own subscription, separate from the phased design fee, even for the same client.
• Keep incremental construction administration billing and the monthly retainer as distinct billing objects when both run at the same time.
• Recalculate remaining phase fees in your project accounting after a value-engineered reduction, then adjust the upcoming phase invoices to match.
• List reimbursable expenses such as printing and travel as separate line items so profitability on the design work stays visible.