I'm designing a responsive site for an Insurance provider but their quote form is extremely long (i've tried to reduce questions but not getting v far). My question is whether i create a responsive mobile form for smartphone (broken into sections etc.) or for the mobile site, should i just put a 'request a callback' function with the preposition that users will not complete a long form on their mobile phones?
You should still provide the form on mobiles, don't assume people won't want to fill it in on their mobile and prevent them from doing so - they've gotten as far as searching for the insurance provider and then selected the 'get a quote' option from their phone so it's a pretty safe assumption that they want to proceed with actually getting a quote.
Insurance forms are complex beasts, people will expect this so should be prepared for it being a complicated form. It's not going to be a surprise to them that they request a quote and get shown a huge form - I'd even guess that it'd be more of a surprise if the form was small and brief.
I think you have a few options here though:
It's probably safer to split it over several distinct pages - one for person details, one for details of the item being insured (car, home etc) etc and keep the details stored in the session should the device disconnect for any reason - that makes it easier for them to retrieve the position they were last at if they return to the form.
Difficult to exactly specify what you should do, as insurance forms length and complexity will vary depending on what is being insured, but the general point is: If they can do it on a desktop then they should be able to do it on the mobile. Design the form with the mobile in mind first (field label position, button placement, using input controls that are available on mobiles as well as on desktop browsers etc) so that you don't have to shoehorn in functionality onto the mobile version later on.
As well as the ideas already suggested, how about a third way:
Continue the form on a large device
Or, to avoid the hassle of logging in:
If its necessary, then it is advisable to use the responsive form in mobile. If it can be skipped then you may put Request a callback feature there.
Obviously filling a long form on a mobile device will definitely irritate the user and it will also break couple of the Human Computer Interaction Principle :
Hope this might answered your question.