Streets change over time, as residents' fortunes and architectural fashions move on. Heriot Row is no exception.

Once the street including its corner blocks was complete, the next big event was the opening of the gardens in the space between Heriot Row and Queen Street. The gardens facing the eastern section of Heriot Row opened in 1826. As the trees grew up they screened the Queen Street buildings up the hill and provided a semi-rural view from Heriot Row's front windows.

In 1822, gas lights were installed in the First New Town. According to the City of Edinburgh archives, by Whitsunday 1825, 26 lights were to be installed in Heriot Row and another 20 were added in 1826. Given the high price of oil it was cheaper to replace the original oil lamps with gas lamps. In total, 458 gas lights were installedin the New Town to replace 597 less effective oil lamps.

Practical changes were made in the century that followed to provide more space. Some sloping roofs acquired dormer windows, giving extra light and room, while some occupants added a storey. The downside was the loss of the clear lines of the original palace front in Robert Reid's designs.

Other changes were more decorative. Some houses acquired beautiful cast iron balconies. Then as Victorian technology perfected large sheets of plate glass, the astragals (or wooden window dividers) in many houses were replaced. Often a stone course was removed at the same time, to make the windows deeper.

Changes of use also made their mark. While the street's many lawyers and doctors had regularly worked from home, some residential buildings now became proper offices. A basement flat might be kept for a caretaker, but interiors were remodelled and some of the lovely Georgian fireplaces and mouldings disappeared. The water supply, originally piped just to the basement, extended throughout the houses, and bathrooms (replacing dry closets) were created out of bedrooms. Candles and oil lamps gave way to gas and electricity.

As the 20th century advanced, so did the offices. By 1947, Edinburgh's Post Office directory listed many solicitors, advocates and doctors along the street. More houses were sub-divided, mews stables became garages or flats and by the 1950s Heriot Row East had lost its setts (rectangular cobbles of dressed stone), although they survived in Heriot Row West. Robert Lorimer's 1920s work at Number 6 was a rare example of architecturally distinguished change in the street.

When the Edinburgh New Town Conservation Committee was set up in 1970, new efforts to respect and nurture the Second New Town bore fruit. Advice and grants helped halt decay and tighter planning controls discouraged inappropriate use. Some owners were happy to adopt Georgian colours for their outside paintwork and to replace lost astragals and fanlights. A more ambitious scheme to restore Heriot Row to nearer its original appearance, including the roofline, did not attract residents' support because of the expense and loss of space involved.

Now, more office properties have returned to housing use, and some divided houses have been reunited. So in many ways the street is more like its early self. The strength and durability of its stone construction should allow it to flourish for centuries yet. Its A-listed status and place within Edinburgh's World Heritage site are meant to give it strong protection.

There are still challenges. Major threats in the 20th century of inner ring roads and car parks replacing gardens were overcome. Today, residents worry about car parking, speeding traffic and waste collection. But pride and satisfaction with the street is very high. There is a wider public benefit in protecting the look of the street for its historical and architectural value, its appeal to tourists and its value for future generations.

Over the last decade, more office properties have returned to housing use, and some divided houses have been reunited