In case i wanted to consolidate you advise me for example to send 1 entire bitcoin from my ledger to an other address of my ledger and keep everything saved until now in a new unused address belonging to my ledger nano s?
I have no experience using a Ledger, so can't tell you the details. If it's possible to select which inputs to use, you can manually select just the small amounts. There's no need to put all your funds in one output, you can keep several larger ones in different addresses.
Will it take long for Ledger nano s to consolidate everything to 1 address?
It's just a normal transaction; it takes as long as any other transaction.
However, if you're not in a rush, it's worth using as low a fee as possible. It can take longer to confirm, but you pay less fees.
Just make sure to double check the address you're sending to, but that's a warning that applies to all transactions you make.