On a good bike with a good chain and cogs and properly lubricated cables and derailers there should be no significant difference between shifting on a shop stand and shifting while riding, in terms of the indexing adjustments.
Where you may encounter a problem is when shifting under load while riding, especially with the front derailer. The tension on the chain will make shifting more difficult, requiring a bit of "overshift", especially when moving to a larger cog.
Chain wear can also be a problem. The chain is the first part to wear out on a bike, and failing to replace the chain when worn (after 1000-2000 miles) will cause uneven wear on the cogs, resulting in increased difficulty when shifting, especially under load. And even when the chain is replaced at regular intervals, the rear cluster will wear out after about 5 thousand miles and the front chainrings after 10 thousand or so, making shifting more difficult (and sometimes a bit more of an "adventure").