I work for a small company that hasn't done much work in bespoke development. It's something we're growing into. With all our projects, whether a bespoke development piece of work, or a simple brochure website, we plan out how long we expect the job to take us and then multiply that by our daily fee to give us a quote for the customer.
That has always worked well for us with the smaller projects, the CMS sites, the eCommerce sites, where we know the systems well and don't come across many issues. We have timings down well and can predict costs accurately.
However with these larger bespoke projects we're starting to find that no matter how much we plan ahead, no matter how much we nail the specifications of the system, our timings are always out. We've started adding in a considerable buffer for bespoke pieces of software, but even then a couple of nasty bugs can really set things back and push us beyond what we expect by quite a long way.
How do you quote for these larger projects? Is it simply a case of keep going and eventually we'll get it right? Or are we missing something here as it seems almost impossible to nail pricing down for bespoke websites that fall outside our standard CMS or eCommerce site.
As @Zeroth pointed out there's probably a few things missing out about the team. We don't run sprints. We have one large project on the go and have milestones and just set goals based on our estimates of how long things should take.
As for the team, currently it's made up of 4 people, although 2 new people are being trained up at the moment. The 4 people make up a salesman and designer (he's also the office manager), a designer and website builder, a website builder who also deals with content for the sites and day to day customer facing issues, and me, the developer. I deal with development of custom projects and improving / fixing our CMS and eCommerce platforms. The two people being trained up are another designer and website builder, and a junior developer.
Once a project reaches certain milestones, everyone pitches in to test it as thoroughly as we can. I always put in as much logging and debugging information as I can think of to help track down the inevitable bugs as quickly as possible, but no matter how much we do, we can't test every situation.
I understand this is a complex and widely varying answer, I guess I'm mostly after some advice and also some pointers to resources (thank you @MichaelT for the link to the book) that can help us improve. We need to be able to pull a profit from custom work as we're currently fully booked until June for development work and we need to make this work for us. Over the last year, it just seems no matter how much we learn from each project we work on, we still get it wrong with our estimates.