I know some towns hold their own records
Very few in Scotland.
Most small towns kept archives of some types - mostly records of the proceedings of their town/burgh councils and matters related to local government.
However in 1975 all the small town and burgh councils, along with the county councils, were swept away in a major reorganisation of local government. Scotland was reorganised into a new system of local government involving nine regional councils, 59 district councils, of which 4 were cities (Aberdeen, Dundee, Edinburgh and Glasgow) and 3 islands councils. In 1995 there was a further reorganisation in which the regional councils were abolished and the districts realigned to leave just 32 councils to cover the whole country.
In 1975 the archives of the towns, burghs, cities and county councils came under the care of either the new regional councils or the new district councils, depending on the subject. Social work, for example, was a regional council function, so all the records relating to the poor law went to regional council archives. Burial grounds was a district council function so records relating to burials went to district councils.
In 1995 it was all change again. Some regional council archives were split among the new councils in their areas. For example burial records tended to go to whichever council now looks after the particular burial ground. In other cases, the regional archives went to one of the councils. For instance, the Grampian regional archives are now mostly in the care of Aberdeen City archives, even though they may refer to records created outside the city.
So the only towns that have their own archives now are the four cities. All the archives of all other towns are either in the new council's archives or in an archive sub-contracted by the new council to look after them.
In the case of Angus, the records of Arbroath, Brechin, Carnoustie, Forfar, Kirriemuir, Monifieth and Montrose, and those of Angus County Council, are held by Angus Archives, while the City of Dundee has its own archives.
In some ways it makes life easier because you can access all of the archives of Angus under one roof, or two if you include Dundee. But it also means that in some parts of the country you need to do a bit of investigation beforehand to find out exactly where the documents you want are being held.
Suppose, for example, you are looking for material relating to an ancestor who lived in the parish of Alvah in Banffshire. This would have come under Banff County Council. In 1975, it became part of the new district of Banff and Buchan. Its burial records went to Banff and Buchan District Council, but its Parochial Board (poor law) records went to Grampian Regional Council. In 1995 Banff and Buchan District was amalgamated with Gordon District and Kincardine and Deeside District to form a new council area which (regrettably, because it causes confusion with the historic county) was named Aberdeenshire. The new Aberdeenshire Council arranged for the archives it inherited from Grampian Regional Council and the three previous district councils to be looked after by the City of Aberdeen Archives. So if you want to look at the Alvah parochial board records you have to go to Aberdeen, but the burial records are in Banff under the care of Aberdeenshire Council.