The use of a good quality flushing detergent will enhance the capabilities of the engine oil to do its job, by removing sludge and combustion deposits. There are a few misconceptions about the use of flushing detergents, some say it led to oil leaks after its use, but it maybe that by removing the old sludge from around seals and gasket faces it has shown up the poor condition the engine was in, whilst others fear that the released sludge will block small oil galleries and lead to trouble. Modern oils do contain a percentage of detergent to help with harmful deposits, but a good quality flushing agent is purely a detergent and only performs this task.
If going down the line of using a flushing detergent follow the instruction, usually adding the flush to a warm engine, let the engine idle for 10 to15 minutes then drain the sump in the normal way and replace the oil filter. If an engine flush was needed the drained oil will look "dirtier" showing the detergent has done the job. Preferably next you refill with fresh oil and a new oil filter and give the engine another warm up cycle them drain the oil and change the filter again. This removes any residual deposits and any remaining detergent, remember the flush has few lubricating properties. Refill with a quality oil and filter and the job is done.
The choice of using an engine oil flush is up to the individual but remember the pros and cons, if the engine is an older high mileage unit it may be that it is the sludge that is keeping it oil tight
I do not know if this will help you decide, I hope so.