Tenant shall be responsible for normal wear and tear

[George Wang]

My friend's landlord in NJ just added "Tenant shall be responsible for repairs caused by tenants including wear, tear, and everyday usage" to their lease renew, I am wondering

1. Is this legal and will it hold up in court? 
2. Are my friends screwed if they sign it?
3. I know by law safety deposits are protected from wear and tear but can the landlord still send a bill to tenants or debt collectors?
4. The lease is up 30 days and the landlord gave them 1 day to sign it. If they can't find a new place to live, can they hold over the property?
5. if you have any additional advice to offer...

Thanks!