If so, make sure you apply it.2) If the lease prevents long term guests, you can give them a notice on this, if not, you can potentially require them to add the guest to the lease, although depending on your state you only have a certain amount of time period from when you first become aware to when you can require them to be added3) Do you have an anti smoking clause?

I am not anti nimby (proud nimby here).  

@Evan O'BrienI know many people are anti-agents, but just list with a real estate agent. 

I watched a few videos where the people said it doesn't actually clean the air but rather it keeps the units themselves clean which can prevent the air which is pushed through those units from picking up any toxins that might have started to grow inside the units, thus creating a healthier atmosphere.Since it doesn't clean the air itself it sounds less appealing to me, especially since I would have to be cycling new bulbs in there when they go out.Thoughts?

The area they are moving into is actively anti-mask. 

If you are not aware, Seattle is very pro-tenant and is (IMO) one of the most anti-landlord cities in the nation. 

Typical agenda story with anti-landlord bias.

Every change made in the last 5-10 years has been pro-tenant or anti-landlord, depending how you look at it.

I'm not anti-wholesaling, just remember, they do not represent you or your interests.

Option 2: The Close your Eyes and Wait Act1 - Tell them there's more where they came from, and if they want to eliminate them they should call an exterminator.2 - The cost of the exterminator is not the landlord's responsibility...of course they wouldn't be able to get past the laughing on the other end of their call to the exterminator to worry about any arguments about the cost, and who pays for it.Option 3: The Placebo Act1 - Buy a supply of aspirin (not for you, although you may want to keep some).2 - Put them in a bottle labeled Anti Spider Pills3 - Tell them to save the next spider(s) they kill.4 - Give the bottle to them and tell them to crush the pills. 5 - Mix the crushed pills with the crushed spider and spread them throughout the house.6 - Tell them this works, but only if they do this often since it depends on the quantity of spiders they use...the more the better.This last one should at least keep them busy for a while, and you will have a free "spiders be gone" service.