1995 900s turbo OIL CHANGES ETC

I have had my 1995 900s for about 6 months now, have very few complaints, its nice and fast which does help sometimes :)
just have a quick question in terms of maintance, oil changes, how often
should these be done and does it have to be done by a garage or is it something that i can do.
also, having never owned one of these cars before i have heard that you need different tools for the job i.e metric tools wont fit properly, is this true.
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