B2L2

And landlord supposes to pre-arrange a visiting time.  They have all reason to refuse you if you just go knock on the door (I know, you own that house, but... )

B2L2

Sorry, but I'm on your tenant side in this case here.  It is well known that RTA protects tenant.  So if RTA gets involve in your case, you will have an uphill battle.

1) fridge refers to this one appliance you provided in the unit for the tenant.  So if any part of that fridge is malfunctioned, for me it is reasonable to ask you to fix it.  If you eventually have to replace the fridge without an ice dispenser, I think you better get the agreement with the tenant first as well.

2) dryer pipe/vent.  since your own tendancy agreement doesn't mention about this, RTA will base it off their guideline which means you will have to clean out.  What's a reasonable intervals?  I can't say.  My previous apartment cleans them once a year.  You could hire technician to do that inside the house and it shouldn't cost a lot.  I will just do that if I were you.  Also, sounds like it is a well known problem from the builder.  Has your strata brought this up with the builder?  My previous apartment has an extra blower fan into the dryer pipe to reduce the build up.

Hope this gives you a different view on your case here.

B2L2

Nam, every time you said you're a 包租婆, the 上海婆(沈殿霞) image shows up...  LOL, sorry..

B2L2

If your tenant ask you to reimburse the filter cost, I think you will need to pay for it.

Rental unit that allows pet is actually hard to find and usually cost more.  I'm a dog owner myself, so I'm not against pet.  But don't underestimate what damage a dog could do to your apartment.  My friend's dog once dig a hole thru a drywall in a day.  Of course he need to repair that before he moved out his rental apartment.