Unusually, Scotland is behind England in changing the law. (In most legal matters, Scotland leads and England follows). So the provisions of Section 139 of the Legal Aid, Sentencing and Punishment of Offenders Act 2012, which reduced the 'rehabilitation periods' in England, don't apply in Scotland.
So you need to refer to the tables here (to look for the relevant sentence) and note the rehabilitation period shown in the LEFT-hand column. (In England it's the right-hand column that now applies):
https://www.gov.uk/government/news/reforms-to-help-reduce-reoffending-come-into-force
The Scottish Government announced a year ago that they'd be introducing similar reforms
http://www.telegraph.co.uk/news/uknews/crime/11611077/Slate-wiped-clean-for-more-Scottish-criminals.html
but, unless I've missed it (and Google can't find it), those reforms haven't yet been enacted.
Remember also that when applying for certain types of employment (e.g. working with children or vulnerable adults), convictions never become spent and must always be disclosed. (Just to confuse matters further though, in England a single conviction can, in certain circumstances, become 'protected' and therefore not required to be disclosed, after a certain period of time. It's likely that Scotland will also follow suit).
Further, unless they've got their own legislation regarding 'spent' convictions, a UK conviction can never become spent when the rules of another country apply. So, for example, you will always be ineligible to travel visa-free to the USA; if you want to go there you will have to apply for a visa and attend an interview at the US Embassy in London. (The US Consulate in Edinburgh doesn't deal with visa matters).