What will you be doing in 25 years? Where will you be living and who will you be living with? What will your job be? Who knows? Nobody can predict what they will be doing in quarter of a century, yet businesses are expected to foresee their property requirements for the next 25 years.

The traditional office lease ties occupiers in for 25 years. And at the end of that period they are expected to pay for any repairs required to the building - a controversial area known as ''dilapidations''. Fed up with these restrictions and costs, many occupiers are seeking a more flexible solution to their space requirements. As a result the ''serviced office centre'' has become a growth area in the market.

These offer office space on short term leases - from a single room to extensive suites of offices. The best also provide back-up services such as reception, phone answering, photocopying, security, use of boardrooms, and catering. The idea is that you pay only for what you require - and for as long as you require.

The rentals work out higher per sq ft than those charged in traditional office leases, but for many companies the extra charge is more than offset by the flexibility.

Office centres have become very popular with start-up businesses which have no clear idea as to where they will be in a couple of years. They are also in demand from large companies seeking to set up a branch in a new city.

''Many like the fixed costs,'' says Norman Howison of Glasgow's Woodside House Business Centre. ''We have a lot of UK companies who want a small office in Scotland. This kind of facility allows them to budget accurately. If the presence doesn't work for them, they can pull out without having to find somebody else to take over their lease.''

He says that many tenants sign up initially for a year, but decide to stay for much longer than that. ''We thought that our occupiers would turn over rapidly, but in fact many of them have been with us for several years now. And the demand is tremendous, we've been fully occupied now for the past three years.''

His firm has steadily expanded, and now occupies four adjacent former townhouse buildings at Woodside Place in the city's West End. A couple of similar ventures are located nearby.

For something different occupiers can look to another centre, the Skypark on Finnieston Street. The large-scale facility offers everything from light industrial space to new offices.

Regus, a major provider of serviced office space, has located its Glasgow office right in the centre of the city above the shops on Buchanan Street. For many years regarded as something of a cinderella sector by the big financial institutions, investors are now realising that the area has great potential. Last week Mercury Asset Management became the first institutional investor to back the sector. MAM put some #80m into HQ Executive Offices. The company is now looking for a site in Edinburgh.

The capital seems set for major growth as a wide range of organisations seek a flexible base close to the forthcoming parliament.

Until very recently office occupiers had only two choices when it came to city centre locations - take it or leave it. Offices, it seemed, could not be located anywhere else but right in the heart of the towns and cities.

The advent of the business park over the past decade has changed that pattern. Originally designed in response to the need for open plan space with good car parking, the office park has come of age.

Glasgow was slow to grasp the opportunities, but there is now a range of office parks. Occupiers can choose from Pacific Quay on the former Garden Festival Site, Glasgow Business Park at the M8 at Easterhouse, or several inner-city schemes.

Outside the city there are parks at the airport, as well as a new scheme proposed by Renfrewshire Enterprise. On the east side, Strathclyde Business Park at Bellshill has an impressive list of occupiers.

The South Gyle in Edinburgh has established itself as the most significant business park district in the east of Scotland. The most prestigious of these is Edinburgh Park, home to a growing clutch of top names including Scottish Equitable, ICL, and John Menzies Wholesale.