Limiting resource usage

[<jumpy@tutanota.com>]

https://www.debian.org/doc/manuals/securing-debian-howto/ch4.en.html
4.11.2 Limiting resource usage: the limits.conf file.
$ ulimit -a
core file size          
(blocks, -c) 
data seg size           
(kbytes, -d)
scheduling priority             
(-e)
file size               
(blocks, -f) 
pending signals                 
(-i) 
max locked memory       
(kbytes, -l) 
max memory size         
(kbytes, -m) 
open files                      
(-n) 
pipe size            
(512 bytes, -p) 
POSIX message queues     
(bytes, -q) 
real-time priority              
(-r) 
stack size              
(kbytes, -s) 
cpu time               
(seconds, -t) 
max user processes              
(-u) 
virtual memory          
(kbytes, -v) 
file locks                      
(-x) 

- i cannot change the default setting.
is it a secure feature/the best option or a sign that something is wrong.

- have i to configure limits.conf ?
my /etc/security/limits.conf is not set (all is marked as # comment)
i do not know how-to-do that & i have not found (desktop default user / no server) something that i could copy & past or a soft/script which should generate the best option for me.

- could someone solve that using k.i.s.s. ?

thx by advance in case of responses.
https://www.debian.org/doc/manuals/debian-handbook does not answer at my questions  ),

--
Securely sent with Tutanota.