The landlord cannot skip a step and wont be excused for getting any part of the process wrong SO if fior example your state required a 72 hour notice before the LL can file with the courts asking to evict then the LL MUST do that notice and allow you to have the 72 hours before going and filing. AS to any other warning If your state didn't require a notice to quit or some kind of demand with x number of days before a LL could file then notice doesn't have to be given and the LL can go file , ( My state used to do it that way , a LL didn't have to make a demand first and could just go file once the rent was past due which likely is what caused my state to create a long demand period b4 filing so now every LL I know of has eliminated grace periods from their leases and many finally began to demand last month rent up front too, so they in the end can start the process sooner) SO if the LL has skipped any part of your states process and files to get you into court and you point out what step the LL missed it is likely in court a judge will not allow the matter to proceed and require the LL to start from scratch. I cant speak for the clerks of the courts in your area BUT can tell you that if your LL claims in court that a required notice was given then he /she is going to have to prove it SO if a landlord tells a judge they put it in the mail and the judge asked for proof and LL brought to court her/his certificate of mailing , certified mail, confirmed mail delivery receipts to show the judge the judge should not have a problem believing the LL and would allow the eviction hearing to proceed. ( so im trying to tell you that The LL is the one who has to be able to prove to the court that she/he followed the law , that includes required demand notices & proper service of the summons itself.