Ofsted inspectors will turn up at colleges and training providers with just two weeks' notice under the new inspection regime.
The watchdog stopped short of introducing no-notice inspections, in recognition of the amount of information which institutions need to gather together, but it said it wanted trainers to be in a permanent state of readiness.
With further education institutions being generally more complex than schools, Ofsted decided against matching the two-day or shorter notice period it has adopted for schools.
For colleges, the change may mean just a couple of weeks' less notice, but for work-based learning providers the culture shock is likely to be significant: they have had 12 weeks' notice until now.
Good or outstanding institutions will face inspection less frequently, with some possibly going six years without a visit from Ofsted. However, inspection dates can be brought forward if there is a sudden drop in performance.
When the top-performing colleges and training providers are inspected, they will face more classroom observation than they have done under the former "light-touch" inspection approach, and will have a full team of inspectors arriving.
Melanie Hunt, Ofsted's director of learning and skills, said: "For every learner, this is their main chance, and for those who might be learning in the years between inspections, there is a risk that providers take their foot off the pedal.
"Reducing the notice period for inspections will mean providers are always inspection-ready, so it doesn't become a great once-every-four-years preparation and we see them as they always are."
She denied that ending light-touch inspections amounted to a retreat on the commitment to self-assessment, despite criticism when the Baby P abuse case showed that self-assessment for children's services was flawed.
The new inspection regime will also place more emphasis on obtaining a wider range of views of students and employers. Ms Hunt said: "People thought that when an inspection takes place, there is a selected group who are put in front of the inspectors. We want to look at a variety of different ways of gathering the opinions of learners."
She said many colleges had taken steps to ensure students were represented, so inspectors would be able to approach student governors or representatives and find the best ways of canvassing opinions.
New criteria on supporting diversity, which could affect a college's overall grade, have caused concern because details of how they will be assessed have not been published yet, even though some will face inspection this autumn.
There will also be separate grades for under- and over-19 provision.
Maggie Scott, director of policy at the Association of Colleges, said colleges broadly welcomed the changes, but she thought shorter notice periods would probably be impractical. She also said reintroducing classroom inspections was unlikely to cut internal lesson observations, which some lecturers have said was becoming oppressive.
Editorial, page 32.