The lovely federation and post-federation homes around central Bendigo, Quarry Hill and Flora Hill are gorgeous to live in and pretty average from a security point of view. The original locks were never designed for modern conditions and modern theft methods.
What the original locks usually were
Most federation Bendigo homes had a simple rim lock on the front door, sometimes a mortice lock with a single-throw bolt, and basic latches on the windows. The keys were huge skeleton keys. The security was reasonable for the era - opportunistic petty theft was uncommon and the deterrent value was mostly the door itself rather than the lock.
Why those locks aren't enough now
Single-throw mortice locks can be defeated with basic tools in seconds. Old rim locks have predictable internal patterns and the keys are easy to copy from a single photograph. Window latches that haven't been replaced have lost their tension and don't actually keep the window closed under pressure.
What an upgrade looks like in a heritage home
The challenge is keeping the look. You don't want shiny modern hardware on a 110-year-old door. Most decent residential locksmiths can install modern lock cylinders inside original-looking escutcheons (the decorative metal plates around the keyhole). The visible look stays heritage. The actual lock is modern and secure.
For windows, sash window restrictors are a good compromise. They let the window open for ventilation but stop it from being fully opened from outside. They mount discretely on the frame and don't change the look from the street.
What to budget
For a typical Bendigo federation home with a front door, back door, and four to six windows: $800-$1,500 for a security upgrade that keeps the heritage look. That includes new locking cylinders, modern deadbolts replacing original mortice locks (where appropriate), and window restrictors.
The thing people forget
Sliding back doors and laundry doors are usually the weakest point in a heritage home. The front door is well-protected by the original heavy timber. The back door is often a 1970s add-on with much cheaper hardware. Check there first.