How many services can be used simultaneously?

[7Alex]

I use five services at the same time. Is this the good idea? May phones have performance issues in this case?

 

[Rukbat]

"Services" meaning? Running in the phone? You can run as many services as will run. Some services use almost no resources, some use a lot, and running one of them will show a performance hit. It's like asking how much food you can eat. Peanuts or whole cows? I can eat more peanuts without gaining weight than cows. Running location service doesn't do much to the phone unless an app requests the current location (and then it barely affects performance, and only for a second or less). Running an antivirus scan as a service will slow down any phone.

 

[Francesco Cozzolino1]

Background services (but also foreground services) can be killed by Android when it is running with poor memory.
Some services can even be restarted automatically, depending on how they have been written.
Some more restrictive differences on services and memory management have been introduced starting from Android 4.4.0.