For transactions, it depends on the fee you give. If you give a low fee of lets say 10 satoshis per byte, it may take hours before the first confirmation, while if you pay 200+ satoshis per byte, your transaction can be confirmed in an hour.
It also depends on your service provider for buying/selling BTC but it will normally be under an hour, and as for altcoins, when your order is confirmed on an exchange site, you get it straightaway.
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If you are talking about services like
shapeshift.io, it may vary too and I have heard that it had took a week for the transaction also.
All in all, it really depends on what you are dealing with.
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