Honestly, it depends on the baby.
Some like a routine and so thrive if given one, but would also probably find their own if not.
Some don't, but don't need one, so fall asleep when they need etc even if that varies.
Mine fell into neither camp. She benefitted from a routine, but tore it up quite regularly every 'leap' at least (suggest you read the Wonder Weeks, it's the best baby book). Then she was a hard core tether, so that messed things up more or less solidly from 7 months and 18 months. She also had s very fast metabolism so needed to feed in the night until 18 months ( I stopped the boob in the night then, but after that and even now at three she will often eat some thing boring like an oatcake if she wakes in the night, especially if she's having a growth spurt, and then goes back to sleep much better.
She's dropping her last daytime nap but I don't know when it'll go, it's disappeared and come back several times since she turned two. Mostly theses days she'll sleep for 11/12 hrs through the night and won't nap in the day. But She fell asleep when we got in this afternoon at 5pm, had an hour then was well ready to go to bed at 8.30pm this eve.
The important thing to keep in mind is that your guide should be YOUR BABY and not that smug mum from NCT with the 'slept through at 2 weeks' spiel, your mum / MIL, work colleague, person on the bus etc. Listen to the ideas, by all means, but don't believe their 'silver bullet' suggestions, they worked for their baby not yours. Do what works for you and your baby.
Things went much better when I realised all of that. Happily the smug 'slept through at 2 weeks' people of my aquaintence seems to be having a terrible time with their 2/3/4 year olds whereas DD is stellar on all fronts and we are having a brilliant time 