We all test our 1rep max on lifts such as squats, bench & deadlifts for the same reasons.... to hit a new PB and to FEEL LIKE AN ABSOLUTE BOSS
It's easy to get impatient and want to test your 1RM more frequently than planned to check you are on the right track, however testing your max once every week or so is in no way whatsoever beneficial, and here's why.......
• NOT ENOUGH VOLUME
Most strength gains happen when we lift between 75-90% of our 1RM for multiple sets of 3-5. Lifting 100% of your 1RM for 1rep weekly is just not enough volume for you to see meaningful strength adaptations! Start working in the 75-90% range for 6 to 10 weeks, progressively overloading your sessions most weeks... this will create some positive strength gains
• IT'S FATIGUING AS HELL
When we go for a new PB the level of fatigue we accumulate is unreal, particularly on our CNS (Central Nervous System). After very heavy lifting the CNS for most individuals takes at least a week to recover enough for us to hit some heavy numbers again. So if you're testing your deadlift 1RM on a Monday, and then following this with an intense leg session on Wednesday/Thursday, you are going to struggle! You have not recovered enough! It's not just your CNS, your joints & connective tissue (Ligaments and tendons) are effected too. The connective tissue around your elbows and wrists can kill after a heavy squat session from supporting the bar, which will negatively effect the bench press that you're attempting to get through the following day. So not only is testing your 1RM too frequently not making you stronger... it is also negatively effecting your other sessions!!!
• TECHNIQUE PRACTICE
A 1 rep max is very rarely a pretty rep. If it's absolutely perfect, its probably not your 1 rep max! Practicing a 1 rep max weekly with poor form is going to get you good at one thing..... Lifting with poor form!!! As mentioned above, lower the weight and stick to the 75-90% range to get strong and to PERFECT YOUR TECHNIQUE
• YOU'VE NOT PEAKED
Once you've been training in the 75-90% range for 6+weeks, you can then spend around 3/4 weeks lifting 90-97.5% of your max for multiple sets of 1-3, working on that technique under a heavy load and preparing the body for a 1rep max test. After a few days recovering, making sure that your sleep is perfect and ensuring you have fully replenished any depleted Glycogen stores... you're good to go! Testing your max every 1-2 weeks means you simply cannot peak in this fashion, therefore you're not ready to break your personal record!!!
If you truly want to get stronger and see a difference, invest in a periodized strength plan that's specific to you, progressively overloading and peaks you ready for your 1 rep max testing, then you will experience true strength gains!