LUA timers explanation

[Bitver]

Describe your task in more detail. It all depends on what kind of timer is needed and what additional logic is there. Scheduled script can be ok for longer time periods where timer precision does not matter much. timerfd + select provides the best precision but the script becomes more complex.
lbtep() receives a single telegram until a timeout happens while lb:loop(timeout) receives multiple telegrams until the specified timeout expires.

1. Am I right if I say that better precision loads CPU more?

2. OK, for example I have an idea to implement rx observable in LM to handle complex logic and it requires step timer. 
Precision is +-1 sec and range is "0 sec - several hours"
As I understand, lb:loop(1) with delta correction for better precision is best option for it?

3. Another example is irrigation system where precision +-5 seconds is possible, but it runs in different day in different times configured dinamically by user.
In this case Scheduled script is better or lb:loop(1) with current time checking is still OK?