My questions are:
1.) What are the pros/cons of changing my receiving address for every time I receive a bitcoin to my Hierarchical Deterministic wallet?
There are no cons. The xgood side is that it protects your privacy , as you are giving someone a never used address so no other transaction can be traced to you.
2.) I also noticed that if you have much input in one transaction, the transaction size gets bigger, then it requires some huge fee to confirm my transaction.(Let's say my example transaction above is executed).
- How can I prevent or solve this problem (having a huge fee)?
The number of inputs do not depend on the number of addresses, but number of transactions. You can have 30 inputs in the same address
The solution for this is to consolidate your inputs when fees are low. To do this you just have to do a transaction to your own wallet.
You could do that anytime actually, if you have no hurry. Just set 1/sat per byte and wait .
Guide here by LoyceV
https://bitcointalk.org/index.php?topic=2848987.0